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  • UserAppDataPath in WPF

    - by psheriff
    In Windows Forms applications you were able to get to your user's roaming profile directory very easily using the Application.UserAppDataPath property. This folder allows you to store information for your program in a custom folder specifically for your program. The format of this directory looks like this: C:\Users\YOUR NAME\AppData\Roaming\COMPANY NAME\APPLICATION NAME\APPLICATION VERSION For example, on my Windows 7 64-bit system, this folder would look like this for a Windows Forms Application: C:\Users\PSheriff\AppData\Roaming\PDSA, Inc.\WindowsFormsApplication1\1.0.0.0 For some reason Microsoft did not expose this property from the Application object of WPF applications. I guess they think that we don't need this property in WPF? Well, sometimes we still do need to get at this folder. You have two choices on how to retrieve this property. Add a reference to the System.Windows.Forms.dll to your WPF application and use this property directly. Or, you can write your own method to build the same path. If you add a reference to the System.Windows.Forms.dll you will need to use System.Windows.Forms.Application.UserAppDataPath to access this property. Create a GetUserAppDataPath Method in WPF If you want to build this path you can do so with just a few method calls in WPF using Reflection. The code below shows this fairly simple method to retrieve the same folder as shown above. C#using System.Reflection; public string GetUserAppDataPath(){  string path = string.Empty;  Assembly assm;  Type at;  object[] r;   // Get the .EXE assembly  assm = Assembly.GetEntryAssembly();  // Get a 'Type' of the AssemblyCompanyAttribute  at = typeof(AssemblyCompanyAttribute);  // Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, false);  // Get the Company Attribute  AssemblyCompanyAttribute ct =                 ((AssemblyCompanyAttribute)(r[0]));  // Build the User App Data Path  path = Environment.GetFolderPath(              Environment.SpecialFolder.ApplicationData);  path += @"\" + ct.Company;  path += @"\" + assm.GetName().Version.ToString();   return path;} Visual BasicPublic Function GetUserAppDataPath() As String  Dim path As String = String.Empty  Dim assm As Assembly  Dim at As Type  Dim r As Object()   ' Get the .EXE assembly  assm = Assembly.GetEntryAssembly()  ' Get a 'Type' of the AssemblyCompanyAttribute  at = GetType(AssemblyCompanyAttribute)  ' Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, False)  ' Get the Company Attribute  Dim ct As AssemblyCompanyAttribute = _                 DirectCast(r(0), AssemblyCompanyAttribute)  ' Build the User App Data Path  path = Environment.GetFolderPath( _                 Environment.SpecialFolder.ApplicationData)  path &= "\" & ct.Company  path &= "\" & assm.GetName().Version.ToString()   Return pathEnd Function Summary Getting the User Application Data Path folder in WPF is fairly simple with just a few method calls using Reflection. Of course, there is absolutely no reason you cannot just add a reference to the System.Windows.Forms.dll to your WPF application and use that Application object. After all, System.Windows.Forms.dll is a part of the .NET Framework and can be used from WPF with no issues at all. NOTE: Visit http://www.pdsa.com/downloads to get more tips and tricks like this one. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • A WPF Image Button

    - by psheriff
    Instead of a normal button with words, sometimes you want a button that is just graphical. Yes, you can put an Image control in the Content of a normal Button control, but you still have the button outline, and trying to change the style can be rather difficult. Instead I like creating a user control that simulates a button, but just accepts an image. Figure 1 shows an example of three of these custom user controls to represent minimize, maximize and close buttons for a borderless window. Notice the highlighted image button has a gray rectangle around it. You will learn how to highlight using the VisualStateManager in this blog post.Figure 1: Creating a custom user control for things like image buttons gives you complete control over the look and feel.I would suggest you read my previous blog post on creating a custom Button user control as that is a good primer for what I am going to expand upon in this blog post. You can find this blog post at http://weblogs.asp.net/psheriff/archive/2012/08/10/create-your-own-wpf-button-user-controls.aspx.The User ControlThe XAML for this image button user control contains just a few controls, plus a Visual State Manager. The basic outline of the user control is shown below:<Border Grid.Row="0"        Name="borMain"        Style="{StaticResource pdsaButtonImageBorderStyle}"        MouseEnter="borMain_MouseEnter"        MouseLeave="borMain_MouseLeave"        MouseLeftButtonDown="borMain_MouseLeftButtonDown">  <VisualStateManager.VisualStateGroups>  ... MORE XAML HERE ...  </VisualStateManager.VisualStateGroups>  <Image Style="{StaticResource pdsaButtonImageImageStyle}"         Visibility="{Binding Path=Visibility}"         Source="{Binding Path=ImageUri}"         ToolTip="{Binding Path=ToolTip}" /></Border>There is a Border control named borMain and a single Image control in this user control. That is all that is needed to display the buttons shown in Figure 1. The definition for this user control is in a DLL named PDSA.WPF. The Style definitions for both the Border and the Image controls are contained in a resource dictionary names PDSAButtonStyles.xaml. Using a resource dictionary allows you to create a few different resource dictionaries, each with a different theme for the buttons.The Visual State ManagerTo display the highlight around the button as your mouse moves over the control, you will need to add a Visual State Manager group. Two different states are needed; MouseEnter and MouseLeave. In the MouseEnter you create a ColorAnimation to modify the BorderBrush color of the Border control. You specify the color to animate as “DarkGray”. You set the duration to less than a second. The TargetName of this storyboard is the name of the Border control “borMain” and since we are specifying a single color, you need to set the TargetProperty to “BorderBrush.Color”. You do not need any storyboard for the MouseLeave state. Leaving this VisualState empty tells the Visual State Manager to put everything back the way it was before the MouseEnter event.<VisualStateManager.VisualStateGroups>  <VisualStateGroup Name="MouseStates">    <VisualState Name="MouseEnter">      <Storyboard>        <ColorAnimation             To="DarkGray"            Duration="0:0:00.1"            Storyboard.TargetName="borMain"            Storyboard.TargetProperty="BorderBrush.Color" />      </Storyboard>    </VisualState>    <VisualState Name="MouseLeave" />  </VisualStateGroup></VisualStateManager.VisualStateGroups>Writing the Mouse EventsTo trigger the Visual State Manager to run its storyboard in response to the specified event, you need to respond to the MouseEnter event on the Border control. In the code behind for this event call the GoToElementState() method of the VisualStateManager class exposed by the user control. To this method you will pass in the target element (“borMain”) and the state (“MouseEnter”). The VisualStateManager will then run the storyboard contained within the defined state in the XAML.private void borMain_MouseEnter(object sender,  MouseEventArgs e){  VisualStateManager.GoToElementState(borMain,    "MouseEnter", true);}You also need to respond to the MouseLeave event. In this event you call the VisualStateManager as well, but specify “MouseLeave” as the state to go to.private void borMain_MouseLeave(object sender, MouseEventArgs e){  VisualStateManager.GoToElementState(borMain,     "MouseLeave", true);}The Resource DictionaryBelow is the definition of the PDSAButtonStyles.xaml resource dictionary file contained in the PDSA.WPF DLL. This dictionary can be used as the default look and feel for any image button control you add to a window. <ResourceDictionary  ... >  <!-- ************************* -->  <!-- ** Image Button Styles ** -->  <!-- ************************* -->  <!-- Image/Text Button Border -->  <Style TargetType="Border"         x:Key="pdsaButtonImageBorderStyle">    <Setter Property="Margin"            Value="4" />    <Setter Property="Padding"            Value="2" />    <Setter Property="BorderBrush"            Value="Transparent" />    <Setter Property="BorderThickness"            Value="1" />    <Setter Property="VerticalAlignment"            Value="Top" />    <Setter Property="HorizontalAlignment"            Value="Left" />    <Setter Property="Background"            Value="Transparent" />  </Style>  <!-- Image Button -->  <Style TargetType="Image"         x:Key="pdsaButtonImageImageStyle">    <Setter Property="Width"            Value="40" />    <Setter Property="Margin"            Value="6" />    <Setter Property="VerticalAlignment"            Value="Top" />    <Setter Property="HorizontalAlignment"            Value="Left" />  </Style></ResourceDictionary>Using the Button ControlOnce you make a reference to the PDSA.WPF DLL from your WPF application you will see the “PDSAucButtonImage” control appear in your Toolbox. Drag and drop the button onto a Window or User Control in your application. I have not referenced the PDSAButtonStyles.xaml file within the control itself so you do need to add a reference to this resource dictionary somewhere in your application such as in the App.xaml.<Application.Resources>  <ResourceDictionary>    <ResourceDictionary.MergedDictionaries>      <ResourceDictionary         Source="/PDSA.WPF;component/PDSAButtonStyles.xaml" />    </ResourceDictionary.MergedDictionaries>  </ResourceDictionary></Application.Resources>This will give your buttons a default look and feel unless you override that dictionary on a specific Window or User Control or on an individual button. After you have given a global style to your application and you drag your image button onto a window, the following will appear in your XAML window.<my:PDSAucButtonImage ... />There will be some other attributes set on the above XAML, but you simply need to set the x:Name, the ToolTip and ImageUri properties. You will also want to respond to the Click event procedure in order to associate an action with clicking on this button. In the sample code you download for this blog post you will find the declaration of the Minimize button to be the following:<my:PDSAucButtonImage       x:Name="btnMinimize"       Click="btnMinimize_Click"       ToolTip="Minimize Application"       ImageUri="/PDSA.WPF;component/Images/Minus.png" />The ImageUri property is a dependency property in the PDSAucButtonImage user control. The x:Name and the ToolTip we get for free. You have to create the Click event procedure yourself. This is also created in the PDSAucButtonImage user control as follows:private void borMain_MouseLeftButtonDown(object sender,  MouseButtonEventArgs e){  RaiseClick(e);}public delegate void ClickEventHandler(object sender,  RoutedEventArgs e);public event ClickEventHandler Click;protected void RaiseClick(RoutedEventArgs e){  if (null != Click)    Click(this, e);}Since a Border control does not have a Click event you will create one by using the MouseLeftButtonDown on the border to fire an event you create called “Click”.SummaryCreating your own image button control can be done in a variety of ways. In this blog post I showed you how to create a custom user control and simulate a button using a Border and Image control. With just a little bit of code to respond to the MouseLeftButtonDown event on the border you can raise your own Click event. Dependency properties, such as ImageUri, allow you to set attributes on your custom user control. Feel free to expand on this button by adding additional dependency properties, change the resource dictionary, and even the animation to make this button look and act like you want.NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A WPF Image  Button” from the drop down list.

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  • Using a WPF ListView as a DataGrid

    - by psheriff
    Many people like to view data in a grid format of rows and columns. WPF did not come with a data grid control that automatically creates rows and columns for you based on the object you pass it. However, the WPF Toolkit can be downloaded from CodePlex.com that does contain a DataGrid control. This DataGrid gives you the ability to pass it a DataTable or a Collection class and it will automatically figure out the columns or properties and create all the columns for you and display the data.The DataGrid control also supports editing and many other features that you might not always need. This means that the DataGrid does take a little more time to render the data. If you want to just display data (see Figure 1) in a grid format, then a ListView works quite well for this task. Of course, you will need to create the columns for the ListView, but with just a little generic code, you can create the columns on the fly just like the WPF Toolkit’s DataGrid. Figure 1: A List of Data using a ListView A Simple ListView ControlThe XAML below is what you would use to create the ListView shown in Figure 1. However, the problem with using XAML is you have to pre-define the columns. You cannot re-use this ListView except for “Product” data. <ListView x:Name="lstData"          ItemsSource="{Binding}">  <ListView.View>    <GridView>      <GridViewColumn Header="Product ID"                      Width="Auto"               DisplayMemberBinding="{Binding Path=ProductId}" />      <GridViewColumn Header="Product Name"                      Width="Auto"               DisplayMemberBinding="{Binding Path=ProductName}" />      <GridViewColumn Header="Price"                      Width="Auto"               DisplayMemberBinding="{Binding Path=Price}" />    </GridView>  </ListView.View></ListView> So, instead of creating the GridViewColumn’s in XAML, let’s learn to create them in code to create any amount of columns in a ListView. Create GridViewColumn’s From Data TableTo display multiple columns in a ListView control you need to set its View property to a GridView collection object. You add GridViewColumn objects to the GridView collection and assign the GridView to the View property. Each GridViewColumn object needs to be bound to a column or property name of the object that the ListView will be bound to. An ADO.NET DataTable object contains a collection of columns, and these columns have a ColumnName property which you use to bind to the GridViewColumn objects. Listing 1 shows a sample of reading and XML file into a DataSet object. After reading the data a GridView object is created. You can then loop through the DataTable columns collection and create a GridViewColumn object for each column in the DataTable. Notice the DisplayMemberBinding property is set to a new Binding to the ColumnName in the DataTable. C#private void FirstSample(){  // Read the data  DataSet ds = new DataSet();  ds.ReadXml(GetCurrentDirectory() + @"\Xml\Product.xml");    // Create the GridView  GridView gv = new GridView();   // Create the GridView Columns  foreach (DataColumn item in ds.Tables[0].Columns)  {    GridViewColumn gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.ColumnName);    gvc.Header = item.ColumnName;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   // Setup the GridView Columns  lstData.View = gv;  // Display the Data  lstData.DataContext = ds.Tables[0];} VB.NETPrivate Sub FirstSample()  ' Read the data  Dim ds As New DataSet()  ds.ReadXml(GetCurrentDirectory() & "\Xml\Product.xml")   ' Create the GridView  Dim gv As New GridView()   ' Create the GridView Columns  For Each item As DataColumn In ds.Tables(0).Columns    Dim gvc As New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.ColumnName)    gvc.Header = item.ColumnName    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   ' Setup the GridView Columns  lstData.View = gv  ' Display the Data  lstData.DataContext = ds.Tables(0)End SubListing 1: Loop through the DataTable columns collection to create GridViewColumn objects A Generic Method for Creating a GridViewInstead of having to write the code shown in Listing 1 for each ListView you wish to create, you can create a generic method that given any DataTable will return a GridView column collection. Listing 2 shows how you can simplify the code in Listing 1 by setting up a class called WPFListViewCommon and create a method called CreateGridViewColumns that returns your GridView. C#private void DataTableSample(){  // Read the data  DataSet ds = new DataSet();  ds.ReadXml(GetCurrentDirectory() + @"\Xml\Product.xml");   // Setup the GridView Columns  lstData.View =      WPFListViewCommon.CreateGridViewColumns(ds.Tables[0]);  lstData.DataContext = ds.Tables[0];} VB.NETPrivate Sub DataTableSample()  ' Read the data  Dim ds As New DataSet()  ds.ReadXml(GetCurrentDirectory() & "\Xml\Product.xml")   ' Setup the GridView Columns  lstData.View = _      WPFListViewCommon.CreateGridViewColumns(ds.Tables(0))  lstData.DataContext = ds.Tables(0)End SubListing 2: Call a generic method to create GridViewColumns. The CreateGridViewColumns MethodThe CreateGridViewColumns method will take a DataTable as a parameter and create a GridView object with a GridViewColumn object in its collection for each column in your DataTable. C#public static GridView CreateGridViewColumns(DataTable dt){  // Create the GridView  GridView gv = new GridView();  gv.AllowsColumnReorder = true;   // Create the GridView Columns  foreach (DataColumn item in dt.Columns)  {    GridViewColumn gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.ColumnName);    gvc.Header = item.ColumnName;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   return gv;} VB.NETPublic Shared Function CreateGridViewColumns _  (ByVal dt As DataTable) As GridView  ' Create the GridView  Dim gv As New GridView()  gv.AllowsColumnReorder = True   ' Create the GridView Columns  For Each item As DataColumn In dt.Columns    Dim gvc As New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.ColumnName)    gvc.Header = item.ColumnName    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   Return gvEnd FunctionListing 3: The CreateGridViewColumns method takes a DataTable and creates GridViewColumn objects in a GridView. By separating this method out into a class you can call this method anytime you want to create a ListView with a collection of columns from a DataTable. SummaryIn this blog you learned how to create a ListView that acts like a DataGrid. You are able to use a DataTable as both the source of the data, and for creating the columns for the ListView. In the next blog entry you will learn how to use the same technique, but for Collection classes. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "WPF ListView as a DataGrid" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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  • Control to Control Binding in WPF/Silverlight

    - by psheriff
    In the past if you had two controls that you needed to work together, you would have to write code. For example, if you want a label control to display any text a user typed into a text box you would write code to do that. If you want turn off a set of controls when a user checks a check box, you would also have to write code. However, with XAML, these operations become very easy to do. Bind Text Box to Text Block As a basic example of this functionality, let’s bind a TextBlock control to a TextBox. When the user types into a TextBox the value typed in will show up in the TextBlock control as well. To try this out, create a new Silverlight or WPF application in Visual Studio. On the main window or user control type in the following XAML. <StackPanel>  <TextBox Margin="10" x:Name="txtData" />  <TextBlock Margin="10"              Text="{Binding ElementName=txtData,                             Path=Text}" /></StackPanel> Now run the application and type into the TextBox control. As you type you will see the data you type also appear in the TextBlock control. The {Binding} markup extension is responsible for this behavior. You set the ElementName attribute of the Binding markup to the name of the control that you wish to bind to. You then set the Path attribute to the name of the property of that control you wish to bind to. That’s all there is to it! Bind the IsEnabled Property Now let’s apply this concept to something that you might use in a business application. Consider the following two screen shots. The idea is that if the Add Benefits check box is un-checked, then the IsEnabled property of the three “Benefits” check boxes will be set to false (Figure 1). If the Add Benefits check box is checked, then the IsEnabled property of the “Benefits” check boxes will be set to true (Figure 2). Figure 1: Uncheck Add Benefits and the Benefits will be disabled. Figure 2: Check Add Benefits and the Benefits will be enabled. To accomplish this, you would write XAML to bind to each of the check boxes in the “Benefits To Add” section to the check box named chkBenefits. Below is a fragment of the XAML code that would be used. <CheckBox x:Name="chkBenefits" /> <CheckBox Content="401k"           IsEnabled="{Binding ElementName=chkBenefits,                               Path=IsChecked}" /> Since the IsEnabled property is a boolean type and the IsChecked property is also a boolean type, you can bind these two together. If they were different types, or if you needed them to set the IsEnabled property to the inverse of the IsChecked property then you would need to use a ValueConverter class. SummaryOnce you understand the basics of data binding in XAML, you can eliminate a lot code. Connecting controls together is as easy as just setting the ElementName and Path properties of the Binding markup extension. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Basic Control Binding" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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  • WPF ListView as a DataGrid – Part 2

    - by psheriff
    In my last blog post I showed you how to create GridViewColumn objects on the fly from the meta-data in a DataTable. By doing this you can create columns for a ListView at runtime instead of having to pre-define each ListView for each different DataTable. Well, many of us use collections of our classes and it would be nice to be able to do the same thing for our collection classes as well. This blog post will show you one approach for using collection classes as the source of the data for your ListView.  Figure 1: A List of Data using a ListView Load Property NamesYou could use reflection to gather the property names in your class, however there are two things wrong with this approach. First, reflection is too slow, and second you may not want to display all your properties from your class in the ListView. Instead of reflection you could just create your own custom collection class of PropertyHeader objects. Each PropertyHeader object will contain a property name and a header text value at a minimum. You could add a width property if you wanted as well. All you need to do is to create a collection of property header objects where each object represents one column in your ListView. Below is a simple example: PropertyHeaders coll = new PropertyHeaders(); coll.Add(new PropertyHeader("ProductId", "Product ID"));coll.Add(new PropertyHeader("ProductName", "Product Name"));coll.Add(new PropertyHeader("Price", "Price")); Once you have this collection created, you could pass this collection to a method that would create the GridViewColumn objects based on the information in this collection. Below is the full code for the PropertyHeader class. Besides the PropertyName and Header properties, there is a constructor that will allow you to set both properties when the object is created. C#public class PropertyHeader{  public PropertyHeader()  {  }   public PropertyHeader(string propertyName, string headerText)  {    PropertyName = propertyName;    HeaderText = headerText;  }   public string PropertyName { get; set; }  public string HeaderText { get; set; }} VB.NETPublic Class PropertyHeader  Public Sub New()  End Sub   Public Sub New(ByVal propName As String, ByVal header As String)    PropertyName = propName    HeaderText = header  End Sub   Private mPropertyName As String  Private mHeaderText As String   Public Property PropertyName() As String    Get      Return mPropertyName    End Get    Set(ByVal value As String)      mPropertyName = value    End Set  End Property   Public Property HeaderText() As String    Get      Return mHeaderText    End Get    Set(ByVal value As String)      mHeaderText = value    End Set  End PropertyEnd Class You can use a Generic List class to create a collection of PropertyHeader objects as shown in the following code. C#public class PropertyHeaders : List<PropertyHeader>{} VB.NETPublic Class PropertyHeaders  Inherits List(Of PropertyHeader)End Class Create Property Header Objects You need to create a method somewhere that will create and return a collection of PropertyHeader objects that will represent the columns you wish to add to your ListView prior to binding your collection class to that ListView. Below is a sample method called GetProperties that builds a list of PropertyHeader objects with properties and headers for a Product object. C#public PropertyHeaders GetProperties(){  PropertyHeaders coll = new PropertyHeaders();   coll.Add(new PropertyHeader("ProductId", "Product ID"));  coll.Add(new PropertyHeader("ProductName", "Product Name"));  coll.Add(new PropertyHeader("Price", "Price"));   return coll;} VB.NETPublic Function GetProperties() As PropertyHeaders  Dim coll As New PropertyHeaders()   coll.Add(New PropertyHeader("ProductId", "Product ID"))  coll.Add(New PropertyHeader("ProductName", "Product Name"))  coll.Add(New PropertyHeader("Price", "Price"))   Return collEnd Function WPFListViewCommon Class Now that you have a collection of PropertyHeader objects you need a method that will create a GridView and a collection of GridViewColumn objects based on this PropertyHeader collection. Below is a static/Shared method that you might put into a class called WPFListViewCommon. C#public static GridView CreateGridViewColumns(  PropertyHeaders properties){  GridView gv;  GridViewColumn gvc;   // Create the GridView  gv = new GridView();  gv.AllowsColumnReorder = true;   // Create the GridView Columns  foreach (PropertyHeader item in properties)  {    gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.PropertyName);    gvc.Header = item.HeaderText;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   return gv;} VB.NETPublic Shared Function CreateGridViewColumns( _    ByVal properties As PropertyHeaders) As GridView  Dim gv As GridView  Dim gvc As GridViewColumn   ' Create the GridView  gv = New GridView()  gv.AllowsColumnReorder = True   ' Create the GridView Columns  For Each item As PropertyHeader In properties    gvc = New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.PropertyName)    gvc.Header = item.HeaderText    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   Return gvEnd Function Build the Product Screen To build the window shown in Figure 1, you might write code like the following: C#private void CollectionSample(){  Product prod = new Product();   // Setup the GridView Columns  lstData.View = WPFListViewCommon.CreateGridViewColumns(       prod.GetProperties());  lstData.DataContext = prod.GetProducts();} VB.NETPrivate Sub CollectionSample()  Dim prod As New Product()   ' Setup the GridView Columns  lstData.View = WPFListViewCommon.CreateGridViewColumns( _       prod.GetProperties())  lstData.DataContext = prod.GetProducts()End Sub The Product class contains a method called GetProperties that returns a PropertyHeaders collection. You pass this collection to the WPFListViewCommon’s CreateGridViewColumns method and it will create a GridView for the ListView. When you then feed the DataContext property of the ListView the Product collection the appropriate columns have already been created and data bound. Summary In this blog you learned how to create a ListView that acts like a DataGrid using a collection class. While it does take a little code to do this, it is an alternative to creating each GridViewColumn in XAML. This gives you a lot of flexibility. You could even read in the property names and header text from an XML file for a truly configurable ListView. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "WPF ListView as a DataGrid – Part 2" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".  

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  • WPF ListView as a DataGrid – Part 3

    - by psheriff
    I have had a lot of great feedback on the blog post about turning the ListView into a DataGrid by creating GridViewColumn objects on the fly. So, in the last 2 parts, I showed a couple of different methods for accomplishing this. Let’s now look at one more and that is use Reflection to extract the properties from a Product, Customer, or Employee object to create the columns. Yes, Reflection is a slower approach, but you could create the columns one time then cache the View object for re-use. Another potential drawback is you may have columns in your object that you do not wish to display on your ListView. But, just because so many people asked, here is how to accomplish this using Reflection.   Figure 1: Use Reflection to create GridViewColumns. Using Reflection to gather property names is actually quite simple. First you need to pass any type (Product, Customer, Employee, etc.) to a method like I did in my last two blog posts on this subject. Below is the method that I created in the WPFListViewCommon class that now uses reflection. C#public static GridView CreateGridViewColumns(Type anyType){  // Create the GridView  GridView gv = new GridView();  GridViewColumn gvc;   // Get the public properties.  PropertyInfo[] propInfo =          anyType.GetProperties(BindingFlags.Public |                                BindingFlags.Instance);   foreach (PropertyInfo item in propInfo)  {    gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.Name);    gvc.Header = item.Name;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   return gv;} VB.NETPublic Shared Function CreateGridViewColumns( _  ByVal anyType As Type) As GridView  ' Create the GridView   Dim gv As New GridView()  Dim gvc As GridViewColumn   ' Get the public properties.   Dim propInfo As PropertyInfo() = _    anyType.GetProperties(BindingFlags.Public Or _                          BindingFlags.Instance)   For Each item As PropertyInfo In propInfo    gvc = New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.Name)    gvc.Header = item.Name    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   Return gvEnd Function The key to using Relection is using the GetProperties method on the type you pass in. When you pass in a Product object as Type, you can now use the GetProperties method and specify, via flags, which properties you wish to return. In the code that I wrote, I am just retrieving the Public properties and only those that are Instance properties. I do not want any static/Shared properties or private properties. GetProperties returns an array of PropertyInfo objects. You can loop through this array and build your GridViewColumn objects by reading the Name property from the PropertyInfo object. Build the Product Screen To populate the ListView shown in Figure 1, you might write code like the following: C#private void CollectionSample(){  Product prod = new Product();   // Setup the GridView Columns  lstData.View =      WPFListViewCommon.CreateGridViewColumns(typeOf(Product));  lstData.DataContext = prod.GetProducts();} VB.NETPrivate Sub CollectionSample()  Dim prod As New Product()   ' Setup the GridView Columns  lstData.View = WPFListViewCommon.CreateGridViewColumns( _       GetType(Product))  lstData.DataContext = prod.GetProducts()End Sub All you need to do now is to pass in a Type object from your Product class that you can get by using the typeOf() function in C# or the GetType() function in VB. That’s all there is to it! Summary There are so many different ways to approach the same problem in programming. That is what makes programming so much fun! In this blog post I showed you how to create ListView columns on the fly using Reflection. This gives you a lot of flexibility without having to write extra code as was done previously. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "WPF ListView as a DataGrid – Part 3" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".  

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  • Synchronize Data between a Silverlight ListBox and a User Control

    - by psheriff
    One of the great things about XAML is the powerful data-binding capabilities. If you load up a list box with a collection of objects, you can display detail data about each object without writing any C# or VB.NET code. Take a look at Figure 1 that shows a collection of Product objects in a list box. When you click on a list box you bind the current Product object selected in the list box to a set of controls in a user control with just a very simple Binding statement in XAML.  Figure 1: Synchronizing a ListBox to a User Control is easy with Data Binding Product and Products Classes To illustrate this data binding feature I am going to just create some local data instead of using a WCF service. The code below shows a Product class that has three properties, namely, ProductId, ProductName and Price. This class also has a constructor that takes 3 parameters and allows us to set the 3 properties in an instance of our Product class. C#public class Product{  public Product(int productId, string productName, decimal price)  {    ProductId = productId;    ProductName = productName;    Price = price;  }   public int ProductId { get; set; }  public string ProductName { get; set; }  public decimal Price { get; set; }} VBPublic Class Product  Public Sub New(ByVal _productId As Integer, _                 ByVal _productName As String, _                 ByVal _price As Decimal)    ProductId = _productId    ProductName = _productName    Price = _price  End Sub   Private mProductId As Integer  Private mProductName As String  Private mPrice As Decimal   Public Property ProductId() As Integer    Get      Return mProductId    End Get    Set(ByVal value As Integer)      mProductId = value    End Set  End Property   Public Property ProductName() As String    Get      Return mProductName    End Get    Set(ByVal value As String)      mProductName = value    End Set  End Property   Public Property Price() As Decimal    Get      Return mPrice    End Get    Set(ByVal value As Decimal)      mPrice = value    End Set  End PropertyEnd Class To fill up a list box you need a collection class of Product objects. The code below creates a generic collection class of Product objects. In the constructor of the Products class I have hard-coded five product objects and added them to the collection. In a real-world application you would get your data through a call to service to fill the list box, but for simplicity and just to illustrate the data binding, I am going to just hard code the data. C#public class Products : List<Product>{  public Products()  {    this.Add(new Product(1, "Microsoft VS.NET 2008", 1000));    this.Add(new Product(2, "Microsoft VS.NET 2010", 1000));    this.Add(new Product(3, "Microsoft Silverlight 4", 1000));    this.Add(new Product(4, "Fundamentals of N-Tier eBook", 20));    this.Add(new Product(5, "ASP.NET Security eBook", 20));  }} VBPublic Class Products  Inherits List(Of Product)   Public Sub New()    Me.Add(New Product(1, "Microsoft VS.NET 2008", 1000))    Me.Add(New Product(2, "Microsoft VS.NET 2010", 1000))    Me.Add(New Product(3, "Microsoft Silverlight 4", 1000))    Me.Add(New Product(4, "Fundamentals of N-Tier eBook", 20))    Me.Add(New Product(5, "ASP.NET Security eBook", 20))  End SubEnd Class The Product Detail User Control Below is a user control (named ucProduct) that is used to display the product detail information seen in the bottom portion of Figure 1. This is very basic XAML that just creates a text block and a text box control for each of the three properties in the Product class. Notice the {Binding Path=[PropertyName]} on each of the text box controls. This means that if the DataContext property of this user control is set to an instance of a Product class, then the data in the properties of that Product object will be displayed in each of the text boxes. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.ucProduct"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  HorizontalAlignment="Left"  VerticalAlignment="Top">  <Grid Margin="4">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />    </Grid.RowDefinitions>    <Grid.ColumnDefinitions>      <ColumnDefinition MinWidth="120" />      <ColumnDefinition />    </Grid.ColumnDefinitions>    <TextBlock Grid.Row="0"               Grid.Column="0"               Text="Product Id" />    <TextBox Grid.Row="0"             Grid.Column="1"             Text="{Binding Path=ProductId}" />    <TextBlock Grid.Row="1"               Grid.Column="0"               Text="Product Name" />    <TextBox Grid.Row="1"             Grid.Column="1"             Text="{Binding Path=ProductName}" />    <TextBlock Grid.Row="2"               Grid.Column="0"               Text="Price" />    <TextBox Grid.Row="2"             Grid.Column="1"             Text="{Binding Path=Price}" />  </Grid></UserControl> Synchronize ListBox with User Control You are now ready to fill the list box with the collection class of Product objects and then bind the SelectedItem of the list box to the Product detail user control. The XAML below is the complete code for Figure 1. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.MainPage"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS"  VerticalAlignment="Top"  HorizontalAlignment="Left">  <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources>  <Grid x:Name="LayoutRoot"        Margin="4"        Background="White">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="*" />    </Grid.RowDefinitions>    <ListBox x:Name="lstData"             Grid.Row="0"             BorderBrush="Black"             BorderThickness="1"             ItemsSource="{Binding                   Source={StaticResource productCollection}}"             DisplayMemberPath="ProductName" />    <src:ucProduct x:Name="prodDetail"                   Grid.Row="1"                   DataContext="{Binding ElementName=lstData,                                          Path=SelectedItem}" />  </Grid></UserControl> The first step to making this happen is to reference the Silverlight project (SL_SyncListBoxAndUserControl_CS) where the Product and Products classes are located. I added this namespace and assigned it a namespace prefix of “src” as shown in the line below: xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS" Next, to use the data from an instance of the Products collection, you create a UserControl.Resources section in the XAML and add a tag that creates an instance of the Products class and assigns it a key of “productCollection”.   <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources> Next, you bind the list box to this productCollection object using the ItemsSource property. You bind the ItemsSource of the list box to the static resource named productCollection. You can then set the DisplayMemberPath attribute of the list box to any property of the Product class that you want. In the XAML below I used the ProductName property. <ListBox x:Name="lstData"         ItemsSource="{Binding             Source={StaticResource productCollection}}"         DisplayMemberPath="ProductName" /> You now need to create an instance of the ucProduct user contol below the list box. You do this by once again referencing the “src” namespace and typing in the name of the user control. You then set the DataContext property on this user control to a binding. The binding uses the ElementName attribute to bind to the list box name, in this case “lstData”. The Path of the data is SelectedItem. These two attributes together tell Silverlight to bind the DataContext to the selected item of the list box. That selected item is a Product object. So, once this is bound, the bindings on each text box in the user control are updated and display the current product information. <src:ucProduct x:Name="prodDetail"               DataContext="{Binding ElementName=lstData,                                      Path=SelectedItem}" /> Summary Once you understand the basics of data binding in XAML, you eliminate a lot code that is otherwise needed to move data into controls and out of controls back into an object. Connecting two controls together is easy by just binding using the ElementName and Path properties of the Binding markup extension. Another good tip out of this blog is use user controls and set the DataContext of the user control to have all of the data on the user control update through the bindings. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Synchronize List Box Data with User Control" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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  • Silverlight Tree View with Multiple Levels

    - by psheriff
    There are many examples of the Silverlight Tree View that you will find on the web, however, most of them only show you how to go to two levels. What if you have more than two levels? This is where understanding exactly how the Hierarchical Data Templates works is vital. In this blog post, I am going to break down how these templates work so you can really understand what is going on underneath the hood. To start, let’s look at the typical two-level Silverlight Tree View that has been hard coded with the values shown below: <sdk:TreeView>  <sdk:TreeViewItem Header="Managers">    <TextBlock Text="Michael" />    <TextBlock Text="Paul" />  </sdk:TreeViewItem>  <sdk:TreeViewItem Header="Supervisors">    <TextBlock Text="John" />    <TextBlock Text="Tim" />    <TextBlock Text="David" />  </sdk:TreeViewItem></sdk:TreeView> Figure 1 shows you how this tree view looks when you run the Silverlight application. Figure 1: A hard-coded, two level Tree View. Next, let’s create three classes to mimic the hard-coded Tree View shown above. First, you need an Employee class and an EmployeeType class. The Employee class simply has one property called Name. The constructor is created to accept a “name” argument that you can use to set the Name property when you create an Employee object. public class Employee{  public Employee(string name)  {    Name = name;  }   public string Name { get; set; }} Finally you create an EmployeeType class. This class has one property called EmpType and contains a generic List<> collection of Employee objects. The property that holds the collection is called Employees. public class EmployeeType{  public EmployeeType(string empType)  {    EmpType = empType;    Employees = new List<Employee>();  }   public string EmpType { get; set; }  public List<Employee> Employees { get; set; }} Finally we have a collection class called EmployeeTypes created using the generic List<> class. It is in the constructor for this class where you will build the collection of EmployeeTypes and fill it with Employee objects: public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;            type = new EmployeeType("Manager");    type.Employees.Add(new Employee("Michael"));    type.Employees.Add(new Employee("Paul"));    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} You now have a data hierarchy in memory (Figure 2) which is what the Tree View control expects to receive as its data source. Figure 2: A hierachial data structure of Employee Types containing a collection of Employee objects. To connect up this hierarchy of data to your Tree View you create an instance of the EmployeeTypes class in XAML as shown in line 13 of Figure 3. The key assigned to this object is “empTypes”. This key is used as the source of data to the entire Tree View by setting the ItemsSource property as shown in Figure 3, Callout #1. Figure 3: You need to start from the bottom up when laying out your templates for a Tree View. The ItemsSource property of the Tree View control is used as the data source in the Hierarchical Data Template with the key of employeeTypeTemplate. In this case there is only one Hierarchical Data Template, so any data you wish to display within that template comes from the collection of Employee Types. The TextBlock control in line 20 uses the EmpType property of the EmployeeType class. You specify the name of the Hierarchical Data Template to use in the ItemTemplate property of the Tree View (Callout #2). For the second (and last) level of the Tree View control you use a normal <DataTemplate> with the name of employeeTemplate (line 14). The Hierarchical Data Template in lines 17-21 sets its ItemTemplate property to the key name of employeeTemplate (Line 19 connects to Line 14). The source of the data for the <DataTemplate> needs to be a property of the EmployeeTypes collection used in the Hierarchical Data Template. In this case that is the Employees property. In the Employees property there is a “Name” property of the Employee class that is used to display the employee name in the second level of the Tree View (Line 15). What is important here is that your lowest level in your Tree View is expressed in a <DataTemplate> and should be listed first in your Resources section. The next level up in your Tree View should be a <HierarchicalDataTemplate> which has its ItemTemplate property set to the key name of the <DataTemplate> and the ItemsSource property set to the data you wish to display in the <DataTemplate>. The Tree View control should have its ItemsSource property set to the data you wish to display in the <HierarchicalDataTemplate> and its ItemTemplate property set to the key name of the <HierarchicalDataTemplate> object. It is in this way that you get the Tree View to display all levels of your hierarchical data structure. Three Levels in a Tree View Now let’s expand upon this concept and use three levels in our Tree View (Figure 4). This Tree View shows that you now have EmployeeTypes at the top of the tree, followed by a small set of employees that themselves manage employees. This means that the EmployeeType class has a collection of Employee objects. Each Employee class has a collection of Employee objects as well. Figure 4: When using 3 levels in your TreeView you will have 2 Hierarchical Data Templates and 1 Data Template. The EmployeeType class has not changed at all from our previous example. However, the Employee class now has one additional property as shown below: public class Employee{  public Employee(string name)  {    Name = name;    ManagedEmployees = new List<Employee>();  }   public string Name { get; set; }  public List<Employee> ManagedEmployees { get; set; }} The next thing that changes in our code is the EmployeeTypes class. The constructor now needs additional code to create a list of managed employees. Below is the new code. public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;    Employee emp;    Employee managed;     type = new EmployeeType("Manager");    emp = new Employee("Michael");    managed = new Employee("John");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Tim");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);     emp = new Employee("Paul");    managed = new Employee("Michael");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Sara");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} Now that you have all of the data built in your classes, you are now ready to hook up this three-level structure to your Tree View. Figure 5 shows the complete XAML needed to hook up your three-level Tree View. You can see in the XAML that there are now two Hierarchical Data Templates and one Data Template. Again you list the Data Template first since that is the lowest level in your Tree View. The next Hierarchical Data Template listed is the next level up from the lowest level, and finally you have a Hierarchical Data Template for the first level in your tree. You need to work your way from the bottom up when creating your Tree View hierarchy. XAML is processed from the top down, so if you attempt to reference a XAML key name that is below where you are referencing it from, you will get a runtime error. Figure 5: For three levels in a Tree View you will need two Hierarchical Data Templates and one Data Template. Each Hierarchical Data Template uses the previous template as its ItemTemplate. The ItemsSource of each Hierarchical Data Template is used to feed the data to the previous template. This is probably the most confusing part about working with the Tree View control. You are expecting the content of the current Hierarchical Data Template to use the properties set in the ItemsSource property of that template. But you need to look to the template lower down in the XAML to see the source of the data as shown in Figure 6. Figure 6: The properties you use within the Content of a template come from the ItemsSource of the next template in the resources section. Summary Understanding how to put together your hierarchy in a Tree View is simple once you understand that you need to work from the bottom up. Start with the bottom node in your Tree View and determine what that will look like and where the data will come from. You then build the next Hierarchical Data Template to feed the data to the previous template you created. You keep doing this for each level in your Tree View until you get to the last level. The data for that last Hierarchical Data Template comes from the ItemsSource in the Tree View itself. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Silverlight TreeView with Multiple Levels” from the drop down list.

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  • WPF Login Verification Using Active Directory

    - by psheriff
    Back in October of 2009 I created a WPF login screen (Figure 1) that just showed how to create the layout for a login screen. That one sample is probably the most downloaded sample we have. So in this blog post, I thought I would update that screen and also hook it up to show how to authenticate your user against Active Directory. Figure 1: Original WPF Login Screen I have updated not only the code behind for this login screen, but also the look and feel as shown in Figure 2. Figure 2: An Updated WPF Login Screen The UI To create the UI for this login screen you can refer to my October of 2009 blog post to see how to create the borderless window. You can then look at the sample code to see how I created the linear gradient brush for the background. There are just a few differences in this screen compared to the old version. First, I changed the key image and instead of using words for the Cancel and Login buttons, I used some icons. Secondly I added a text box to hold the Domain name that you wish to authenticate against. This text box is automatically filled in if you are connected to a network. In the Window_Loaded event procedure of the winLogin window you can retrieve the user’s domain name from the Environment.UserDomainName property. For example: txtDomain.Text = Environment.UserDomainName The ADHelper Class Instead of coding the call to authenticate the user directly in the login screen I created an ADHelper class. This will make it easier if you want to add additional AD calls in the future. The ADHelper class contains just one method at this time called AuthenticateUser. This method authenticates a user name and password against the specified domain. The login screen will gather the credentials from the user such as their user name and password, and also the domain name to authenticate against. To use this ADHelper class you will need to add a reference to the System.DirectoryServices.dll in .NET. The AuthenticateUser Method In order to authenticate a user against your Active Directory you will need to supply a valid LDAP path string to the constructor of the DirectoryEntry class. The LDAP path string will be in the format LDAP://DomainName. You will also pass in the user name and password to the constructor of the DirectoryEntry class as well. With a DirectoryEntry object populated with this LDAP path string, the user name and password you will now pass this object to the constructor of a DirectorySearcher object. You then perform the FindOne method on the DirectorySearcher object. If the DirectorySearcher object returns a SearchResult then the credentials supplied are valid. If the credentials are not valid on the Active Directory then an exception is thrown. C#public bool AuthenticateUser(string domainName, string userName,  string password){  bool ret = false;   try  {    DirectoryEntry de = new DirectoryEntry("LDAP://" + domainName,                                           userName, password);    DirectorySearcher dsearch = new DirectorySearcher(de);    SearchResult results = null;     results = dsearch.FindOne();     ret = true;  }  catch  {    ret = false;  }   return ret;} Visual Basic Public Function AuthenticateUser(ByVal domainName As String, _ ByVal userName As String, ByVal password As String) As Boolean  Dim ret As Boolean = False   Try    Dim de As New DirectoryEntry("LDAP://" & domainName, _                                 userName, password)    Dim dsearch As New DirectorySearcher(de)    Dim results As SearchResult = Nothing     results = dsearch.FindOne()     ret = True  Catch    ret = False  End Try   Return retEnd Function In the Click event procedure under the Login button you will find the following code that will validate the credentials that the user types into the login window. C#private void btnLogin_Click(object sender, RoutedEventArgs e){  ADHelper ad = new ADHelper();   if(ad.AuthenticateUser(txtDomain.Text,         txtUserName.Text, txtPassword.Password))    DialogResult = true;  else    MessageBox.Show("Unable to Authenticate Using the                      Supplied Credentials");} Visual BasicPrivate Sub btnLogin_Click(ByVal sender As Object, _ ByVal e As RoutedEventArgs)  Dim ad As New ADHelper()   If ad.AuthenticateUser(txtDomain.Text, txtUserName.Text, _                         txtPassword.Password) Then    DialogResult = True  Else    MessageBox.Show("Unable to Authenticate Using the                      Supplied Credentials")  End IfEnd Sub Displaying the Login Screen At some point when your application launches, you will need to display your login screen modally. Below is the code that you would call to display the login form (named winLogin in my sample application). This code is called from the main application form, and thus the owner of the login screen is set to “this”. You then call the ShowDialog method on the login screen to have this form displayed modally. After the user clicks on one of the two buttons you need to check to see what the DialogResult property was set to. The DialogResult property is a nullable type and thus you first need to check to see if the value has been set. C# private void DisplayLoginScreen(){  winLogin win = new winLogin();   win.Owner = this;  win.ShowDialog();  if (win.DialogResult.HasValue && win.DialogResult.Value)    MessageBox.Show("User Logged In");  else    this.Close();} Visual Basic Private Sub DisplayLoginScreen()  Dim win As New winLogin()   win.Owner = Me  win.ShowDialog()  If win.DialogResult.HasValue And win.DialogResult.Value Then    MessageBox.Show("User Logged In")  Else    Me.Close()  End IfEnd Sub Summary Creating a nice looking login screen is fairly simple to do in WPF. Using the Active Directory services from a WPF application should make your desktop programming task easier as you do not need to create your own user authentication system. I hope this article gave you some ideas on how to create a login screen in WPF. NOTE: You can download the complete sample code for this blog entry at my website: http://www.pdsa.com/downloads. Click on Tips & Tricks, then select 'WPF Login Verification Using Active Directory' from the drop down list. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • Clean up after Visual Studio

    - by psheriff
    As programmer’s we know that if we create a temporary file during the running of our application we need to make sure it is removed when the application or process is complete. We do this, but why can’t Microsoft do it? Visual Studio leaves tons of temporary files all over your hard drive. This is why, over time, your computer loses hard disk space. This blog post will show you some of the most common places where these files are left and which ones you can safely delete..NET Left OversVisual Studio is a great development environment for creating applications quickly. However, it will leave a lot of miscellaneous files all over your hard drive. There are a few locations on your hard drive that you should be checking to see if there are left-over folders or files that you can delete. I have attempted to gather as much data as I can about the various versions of .NET and operating systems. Of course, your mileage may vary on the folders and files I list here. In fact, this problem is so prevalent that PDSA has created a Computer Cleaner specifically for the Visual Studio developer.  Instructions for downloading our PDSA Developer Utilities (of which Computer Cleaner is one) are at the end of this blog entry.Each version of Visual Studio will create “temporary” files in different folders. The problem is that the files created are not always “temporary”. Most of the time these files do not get cleaned up like they should. Let’s look at some of the folders that you should periodically review and delete files within these folders.Temporary ASP.NET FilesAs you create and run ASP.NET applications from Visual Studio temporary files are placed into the <sysdrive>:\Windows\Microsoft.NET\Framework[64]\<vernum>\Temporary ASP.NET Files folder. The folders and files under this folder can be removed with no harm to your development computer. Do not remove the "Temporary ASP.NET Files" folder itself, just the folders underneath this folder. If you use IIS for ASP.NET development, you may need to run the iisreset.exe utility from the command prompt prior to deleting any files/folder under this folder. IIS will sometimes keep files in use in this folder and iisreset will release the locks so the files/folders can be deleted.Website CacheThis folder is similar to the ASP.NET Temporary Files folder in that it contains files from ASP.NET applications run from Visual Studio. This folder is located in each users local settings folder. The location will be a little different on each operating system. For example on Windows Vista/Windows 7, the folder is located at <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\WebsiteCache. If you are running Windows XP this folder is located at <sysdrive>:\ Documents and Settings\<UserName>\Local Settings\Application Data\Microsoft\WebsiteCache. Check these locations periodically and delete all files and folders under this directory.Visual Studio BackupThis backup folder is used by Visual Studio to store temporary files while you develop in Visual Studio. This folder never gets cleaned out, so you should periodically delete all files and folders under this directory. On Windows XP, this folder is located at <sysdrive>:\Documents and Settings\<UserName>\My Documents\Visual Studio 200[5|8]\Backup Files. On Windows Vista/Windows 7 this folder is located at <sysdrive>:\Users\<UserName>\Documents\Visual Studio 200[5|8]\.Assembly CacheNo, this is not the global assembly cache (GAC). It appears that this cache is only created when doing WPF or Silverlight development with Visual Studio 2008 or Visual Studio 2010. This folder is located in <sysdrive>:\ Users\<UserName>\AppData\Local\assembly\dl3 on Windows Vista/Windows 7. On Windows XP this folder is located at <sysdrive>:\ Documents and Settings\<UserName>\Local Settings\Application Data\assembly. If you have not done any WPF or Silverlight development, you may not find this particular folder on your machine.Project AssembliesThis is yet another folder where Visual Studio stores temporary files. You will find a folder for each project you have opened and worked on. This folder is located at <sysdrive>:\Documents and Settings\<UserName>Local Settings\Application Data\Microsoft\Visual Studio\[8|9].0\ProjectAssemblies on Windows XP. On Microsoft Vista/Windows 7 you will find this folder at <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\Visual Studio\[8|9].0\ProjectAssemblies.Remember not all of these folders will appear on your particular machine. Which ones do show up will depend on what version of Visual Studio you are using, whether or not you are doing desktop or web development, and the operating system you are using.SummaryTaking the time to periodically clean up after Visual Studio will aid in keeping your computer running quickly and increase the space on your hard drive. Another place to make sure you are cleaning up is your TEMP folder. Check your OS settings for the location of your particular TEMP folder and be sure to delete any files in here that are not in use. I routinely clean up the files and folders described in this blog post and I find that I actually eliminate errors in Visual Studio and I increase my hard disk space.NEW! PDSA has just published a “pre-release” of our PDSA Developer Utilities at http://www.pdsa.com/DeveloperUtilities that contains a Computer Cleaner utility which will clean up the above-mentioned folders, as well as a lot of other miscellaneous folders that get Visual Studio build-up. You can download a free trial at http://www.pdsa.com/DeveloperUtilities. If you wish to purchase our utilities through the month of November, 2011 you can use the RSVP code: DUNOV11 to get them for only $39. This is $40 off the regular price.NOTE: You can download this article and many samples like the one shown in this blog entry at my website. http://www.pdsa.com/downloads. Select “Tips and Tricks”, then “Developer Machine Clean Up” from the drop down list.Good Luck with your Coding,Paul Sheriff** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • A Communication System for XAML Applications

    - by psheriff
    In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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  • 'Content' is NOT 'Text' in XAML

    - by psheriff
    One of the key concepts in XAML is that the Content property of a XAML control like a Button or ComboBoxItem does not have to contain just textual data. In fact, Content can be almost any other XAML that you want. To illustrate here is a simple example of how to spruce up your Button controls in Silverlight. Here is some very simple XAML that consists of two Button controls within a StackPanel on a Silverlight User Control. <StackPanel>  <Button Name="btnHome"          HorizontalAlignment="Left"          Content="Home" />  <Button Name="btnLog"          HorizontalAlignment="Left"          Content="Logs" /></StackPanel> The XAML listed above will produce a Silverlight control within a Browser that looks like Figure 1.   Figure 1: Normal button controls are quite boring. With just a little bit of refactoring to move the button attributes into Styles, we can make the buttons look a little better. I am a big believer in Styles, so I typically create a Resources section within my user control where I can factor out the common attribute settings for a particular set of controls. Here is a Resources section that I added to my Silverlight user control. <UserControl.Resources>  <Style TargetType="Button"         x:Key="NormalButton">    <Setter Property="HorizontalAlignment"            Value="Left" />    <Setter Property="MinWidth"            Value="50" />    <Setter Property="Margin"            Value="10" />  </Style></UserControl.Resources> Now back in the XAML within the Grid control I update the Button controls to use the Style attribute and have each button use the Static Resource called NormalButton. <StackPanel>  <Button Name="btnHome"          Style="{StaticResource NormalButton}"          Content="Home" />  <Button Name="btnLog"          Style="{StaticResource NormalButton}"          Content="Logs" /></StackPanel> With the additional attributes set in the Resources section on the Button, the above XAML will now display the two buttons as shown in Figure 2. Figure 2: Use Resources to Make Buttons More Consistent Now let’s re-design these buttons even more. Instead of using words for each button, let’s replace the Content property to use a picture. As they say… a picture is worth a thousand words, so let’s take advantage of that. Modify each of the Button controls and eliminate the Content attribute and instead, insert an <Image> control with the <Button> and the </Button> tags. Add a ToolTip to still display the words you had before in the Content and you will now have better looking buttons, as shown in Figure 3.   Figure 3: Using pictures instead of words can be an effective method of communication The XAML to produce Figure 3 is shown in the following listing: <StackPanel>  <Button Name="btnHome"          ToolTipService.ToolTip="Home"          Style="{StaticResource NormalButton}">    <Image Style="{StaticResource NormalImage}"            Source="Images/Home.jpg" />  </Button>  <Button Name="btnLog"          ToolTipService.ToolTip="Logs"          Style="{StaticResource NormalButton}">    <Image Style="{StaticResource NormalImage}"            Source="Images/Log.jpg" />  </Button></StackPanel> You will also need to add the following XAML to the User Control’s Resources section. <Style TargetType="Image"        x:Key="NormalImage">  <Setter Property="Width"          Value="50" /></Style> Add Multiple Controls to Content Now, since the Content can be whatever we want, you could also modify the Content of each button to be a StackPanel control. Then you can have an image and text within the button. <StackPanel>  <Button Name="btnHome"          ToolTipService.ToolTip="Home"          Style="{StaticResource NormalButton}">    <StackPanel>      <Image Style="{StaticResource NormalImage}"              Source="Images/Home.jpg" />      <TextBlock Text="Home"                  Style="{StaticResource NormalTextBlock}" />    </StackPanel>  </Button>  <Button Name="btnLog"          ToolTipService.ToolTip="Logs"          Style="{StaticResource NormalButton}">    <StackPanel>      <Image Style="{StaticResource NormalImage}"              Source="Images/Log.jpg" />      <TextBlock Text="Logs"                  Style="{StaticResource NormalTextBlock}" />    </StackPanel>  </Button></StackPanel> You will need to add one more resource for the TextBlock control too. <Style TargetType="TextBlock"        x:Key="NormalTextBlock">  <Setter Property="HorizontalAlignment"          Value="Center" /></Style> All of the above will now produce the following:   Figure 4: Add multiple controls to the content to make your buttons even more interesting. Summary While this is a simple example, you can see how XAML Content has great flexibility. You could add a MediaElement control as the content of a Button and play a video within the Button. Not that you would necessarily do this, but it does work. What is nice about adding different content within the Button control is you still get the Click event and other attributes of a button, but it does necessarily look like a normal button. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled "Silverlight XAML for the Complete Novice - Part 1."

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  • Read XML Files using LINQ to XML and Extension Methods

    - by psheriff
    In previous blog posts I have discussed how to use XML files to store data in your applications. I showed you how to read those XML files from your project and get XML from a WCF service. One of the problems with reading XML files is when elements or attributes are missing. If you try to read that missing data, then a null value is returned. This can cause a problem if you are trying to load that data into an object and a null is read. This blog post will show you how to create extension methods to detect null values and return valid values to load into your object. The XML Data An XML data file called Product.xml is located in the \Xml folder of the Silverlight sample project for this blog post. This XML file contains several rows of product data that will be used in each of the samples for this post. Each row has 4 attributes; namely ProductId, ProductName, IntroductionDate and Price. <Products>  <Product ProductId="1"           ProductName="Haystack Code Generator for .NET"           IntroductionDate="07/01/2010"  Price="799" />  <Product ProductId="2"           ProductName="ASP.Net Jumpstart Samples"           IntroductionDate="05/24/2005"  Price="0" />  ...  ...</Products> The Product Class Just as you create an Entity class to map each column in a table to a property in a class, you should do the same for an XML file too. In this case you will create a Product class with properties for each of the attributes in each element of product data. The following code listing shows the Product class. public class Product : CommonBase{  public const string XmlFile = @"Xml/Product.xml";   private string _ProductName;  private int _ProductId;  private DateTime _IntroductionDate;  private decimal _Price;   public string ProductName  {    get { return _ProductName; }    set {      if (_ProductName != value) {        _ProductName = value;        RaisePropertyChanged("ProductName");      }    }  }   public int ProductId  {    get { return _ProductId; }    set {      if (_ProductId != value) {        _ProductId = value;        RaisePropertyChanged("ProductId");      }    }  }   public DateTime IntroductionDate  {    get { return _IntroductionDate; }    set {      if (_IntroductionDate != value) {        _IntroductionDate = value;        RaisePropertyChanged("IntroductionDate");      }    }  }   public decimal Price  {    get { return _Price; }    set {      if (_Price != value) {        _Price = value;        RaisePropertyChanged("Price");      }    }  }} NOTE: The CommonBase class that the Product class inherits from simply implements the INotifyPropertyChanged event in order to inform your XAML UI of any property changes. You can see this class in the sample you download for this blog post. Reading Data When using LINQ to XML you call the Load method of the XElement class to load the XML file. Once the XML file has been loaded, you write a LINQ query to iterate over the “Product” Descendants in the XML file. The “select” portion of the LINQ query creates a new Product object for each row in the XML file. You retrieve each attribute by passing each attribute name to the Attribute() method and retrieving the data from the “Value” property. The Value property will return a null if there is no data, or will return the string value of the attribute. The Convert class is used to convert the value retrieved into the appropriate data type required by the Product class. private void LoadProducts(){  XElement xElem = null;   try  {    xElem = XElement.Load(Product.XmlFile);     // The following will NOT work if you have missing attributes    var products =         from elem in xElem.Descendants("Product")        orderby elem.Attribute("ProductName").Value        select new Product        {          ProductId = Convert.ToInt32(            elem.Attribute("ProductId").Value),          ProductName = Convert.ToString(            elem.Attribute("ProductName").Value),          IntroductionDate = Convert.ToDateTime(            elem.Attribute("IntroductionDate").Value),          Price = Convert.ToDecimal(elem.Attribute("Price").Value)        };     lstData.DataContext = products;  }  catch (Exception ex)  {    MessageBox.Show(ex.Message);  }} This is where the problem comes in. If you have any missing attributes in any of the rows in the XML file, or if the data in the ProductId or IntroductionDate is not of the appropriate type, then this code will fail! The reason? There is no built-in check to ensure that the correct type of data is contained in the XML file. This is where extension methods can come in real handy. Using Extension Methods Instead of using the Convert class to perform type conversions as you just saw, create a set of extension methods attached to the XAttribute class. These extension methods will perform null-checking and ensure that a valid value is passed back instead of an exception being thrown if there is invalid data in your XML file. private void LoadProducts(){  var xElem = XElement.Load(Product.XmlFile);   var products =       from elem in xElem.Descendants("Product")      orderby elem.Attribute("ProductName").Value      select new Product      {        ProductId = elem.Attribute("ProductId").GetAsInteger(),        ProductName = elem.Attribute("ProductName").GetAsString(),        IntroductionDate =            elem.Attribute("IntroductionDate").GetAsDateTime(),        Price = elem.Attribute("Price").GetAsDecimal()      };   lstData.DataContext = products;} Writing Extension Methods To create an extension method you will create a class with any name you like. In the code listing below is a class named XmlExtensionMethods. This listing just shows a couple of the available methods such as GetAsString and GetAsInteger. These methods are just like any other method you would write except when you pass in the parameter you prefix the type with the keyword “this”. This lets the compiler know that it should add this method to the class specified in the parameter. public static class XmlExtensionMethods{  public static string GetAsString(this XAttribute attr)  {    string ret = string.Empty;     if (attr != null && !string.IsNullOrEmpty(attr.Value))    {      ret = attr.Value;    }     return ret;  }   public static int GetAsInteger(this XAttribute attr)  {    int ret = 0;    int value = 0;     if (attr != null && !string.IsNullOrEmpty(attr.Value))    {      if(int.TryParse(attr.Value, out value))        ret = value;    }     return ret;  }   ...  ...} Each of the methods in the XmlExtensionMethods class should inspect the XAttribute to ensure it is not null and that the value in the attribute is not null. If the value is null, then a default value will be returned such as an empty string or a 0 for a numeric value. Summary Extension methods are a great way to simplify your code and provide protection to ensure problems do not occur when reading data. You will probably want to create more extension methods to handle XElement objects as well for when you use element-based XML. Feel free to extend these extension methods to accept a parameter which would be the default value if a null value is detected, or any other parameters you wish. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose “Tips & Tricks”, then "Read XML Files using LINQ to XML and Extension Methods" from the drop-down. Good Luck with your Coding,Paul D. Sheriff  

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  • Tip on Reusing Classes in Different .NET Project Types

    - by psheriff
    All of us have class libraries that we developed for use in our projects. When you create a .NET Class Library project with many classes, you can use that DLL in ASP.NET, Windows Forms and WPF applications. However, for Silverlight and Windows Phone, these .NET Class Libraries cannot be used. The reason is Silverlight and Windows Phone both use a scaled down version of .NET and thus do not have access to the full .NET framework class library. However, there are many classes and functionality that will work in the full .NET and in the scaled down versions that Silverlight and Windows Phone use.Let’s take an example of a class that you might want to use in all of the above mentioned projects. The code listing shown below might be something that you have in a Windows Form or an ASP.NET application. public class StringCommon{  public static bool IsAllLowerCase(string value)  {    return new Regex(@"^([^A-Z])+$").IsMatch(value);  }   public static bool IsAllUpperCase(string value)  {    return new Regex(@"^([^a-z])+$").IsMatch(value);  }} The StringCommon class is very simple with just two methods, but you know that the System.Text.RegularExpressions namespace is available in Silverlight and Windows Phone. Thus, you know that you may reuse this class in your Silverlight and Windows Phone projects. Here is the problem: if you create a Silverlight Class Library project and you right-click on that project in Solution Explorer and choose Add | Add Existing Item… from the menu, the class file StringCommon.cs will be copied from the original location and placed into the Silverlight Class Library project. You now have two files with the same code. If you want to change the code you will now need to change it in two places! This is a maintenance nightmare that you have just created. If you then add this to a Windows Phone Class Library project, you now have three places you need to modify the code! Add As LinkInstead of creating three separate copies of the same class file, you want to leave the original class file in its original location and just create a link to that file from the Silverlight and Windows Phone class libraries. Visual Studio will allow you to do this, but you need to do one additional step in the Add Existing Item dialog (see Figure 1). You will still right mouse click on the project and choose Add | Add Existing Item… from the menu. You will still highlight the file you want to add to your project, but DO NOT click on the Add button. Instead click on the drop down portion of the Add button and choose the “Add As Link” menu item. This will now create a link to the file on disk and will not copy the file into your new project. Figure 1: Add as Link will create a link, not copy the file over. When this linked file is added to your project, there will be a different icon next to that file in the Solution Explorer window. This icon signifies that this is a link to a file in another folder on your hard drive.   Figure 2: The Linked file will have a different icon to show it is a link. Of course, if you have code that will not work in Silverlight or Windows Phone -- because the code has dependencies on features of .NET that are not supported on those platforms – you  can always wrap conditional compilation code around the offending code so it will be removed when compiled in those class libraries. SummaryIn this short blog entry you learned how to reuse one of your class libraries from ASP.NET, Windows Forms or WPF applications in your Silverlight or Windows Phone class libraries. You can do this without creating a maintenance nightmare by using the “Add a Link” feature of the Add Existing Item dialog. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.

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  • Get XML from Server for Use on Windows Phone

    - by psheriff
    When working with mobile devices you always need to take into account bandwidth usage and power consumption. If you are constantly connecting to a server to retrieve data for an input screen, then you might think about moving some of that data down to the phone and cache the data on the phone. An example would be a static list of US State Codes that you are asking the user to select from. Since this is data that does not change very often, this is one set of data that would be great to cache on the phone. Since the Windows Phone does not have an embedded database, you can just use an XML string stored in Isolated Storage. Of course, then you need to figure out how to get data down to the phone. You can either ship it with the application, or connect and retrieve the data from your server one time and thereafter cache it and retrieve it from the cache. In this blog post you will see how to create a WCF service to retrieve data from a Product table in a database and send that data as XML to the phone and store it in Isolated Storage. You will then read that data from Isolated Storage using LINQ to XML and display it in a ListBox. Step 1: Create a Windows Phone Application The first step is to create a Windows Phone application called WP_GetXmlFromDataSet (or whatever you want to call it). On the MainPage.xaml add the following XAML within the “ContentPanel” grid: <StackPanel>  <Button Name="btnGetXml"          Content="Get XML"          Click="btnGetXml_Click" />  <Button Name="btnRead"          Content="Read XML"          IsEnabled="False"          Click="btnRead_Click" />  <ListBox Name="lstData"            Height="430"            ItemsSource="{Binding}"            DisplayMemberPath="ProductName" /></StackPanel> Now it is time to create the WCF Service Application that you will call to get the XML from a table in a SQL Server database. Step 2: Create a WCF Service Application Add a new project to your solution called WP_GetXmlFromDataSet.Services. Delete the IService1.* and Service1.* files and the App_Data folder, as you don’t generally need these items. Add a new WCF Service class called ProductService. In the IProductService class modify the void DoWork() method with the following code: [OperationContract]string GetProductXml(); Open the code behind in the ProductService.svc and create the GetProductXml() method. This method (shown below) will connect up to a database and retrieve data from a Product table. public string GetProductXml(){  string ret = string.Empty;  string sql = string.Empty;  SqlDataAdapter da;  DataSet ds = new DataSet();   sql = "SELECT ProductId, ProductName,";  sql += " IntroductionDate, Price";  sql += " FROM Product";   da = new SqlDataAdapter(sql,    ConfigurationManager.ConnectionStrings["Sandbox"].ConnectionString);   da.Fill(ds);   // Create Attribute based XML  foreach (DataColumn col in ds.Tables[0].Columns)  {    col.ColumnMapping = MappingType.Attribute;  }   ds.DataSetName = "Products";  ds.Tables[0].TableName = "Product";  ret = ds.GetXml();   return ret;} After retrieving the data from the Product table using a DataSet, you will want to set each column’s ColumnMapping property to Attribute. Using attribute based XML will make the data transferred across the wire a little smaller. You then set the DataSetName property to the top-level element name you want to assign to the XML. You then set the TableName property on the DataTable to the name you want each element to be in your XML. The last thing you need to do is to call the GetXml() method on the DataSet object which will return an XML string of the data in your DataSet object. This is the value that you will return from the service call. The XML that is returned from the above call looks like the following: <Products>  <Product ProductId="1"           ProductName="PDSA .NET Productivity Framework"           IntroductionDate="9/3/2010"           Price="5000" />  <Product ProductId="3"           ProductName="Haystack Code Generator for .NET"           IntroductionDate="7/1/2010"           Price="599.00" />  ...  ...  ... </Products> The GetProductXml() method uses a connection string from the Web.Config file, so add a <connectionStrings> element to the Web.Config file in your WCF Service application. Modify the settings shown below as needed for your server and database name. <connectionStrings>  <add name="Sandbox"        connectionString="Server=Localhost;Database=Sandbox;                         Integrated Security=Yes"/></connectionStrings> The Product Table You will need a Product table that you can read data from. I used the following structure for my product table. Add any data you want to this table after you create it in your database. CREATE TABLE Product(  ProductId int PRIMARY KEY IDENTITY(1,1) NOT NULL,  ProductName varchar(50) NOT NULL,  IntroductionDate datetime NULL,  Price money NULL) Step 3: Connect to WCF Service from Windows Phone Application Back in your Windows Phone application you will now need to add a Service Reference to the WCF Service application you just created. Right-mouse click on the Windows Phone Project and choose Add Service Reference… from the context menu. Click on the Discover button. In the Namespace text box enter “ProductServiceRefrence”, then click the OK button. If you entered everything correctly, Visual Studio will generate some code that allows you to connect to your Product service. On the MainPage.xaml designer window double click on the Get XML button to generate the Click event procedure for this button. In the Click event procedure make a call to a GetXmlFromServer() method. This method will also need a “Completed” event procedure to be written since all communication with a WCF Service from Windows Phone must be asynchronous.  Write these two methods as follows: private const string KEY_NAME = "ProductData"; private void GetXmlFromServer(){  ProductServiceClient client = new ProductServiceClient();   client.GetProductXmlCompleted += new     EventHandler<GetProductXmlCompletedEventArgs>      (client_GetProductXmlCompleted);   client.GetProductXmlAsync();  client.CloseAsync();} void client_GetProductXmlCompleted(object sender,                                   GetProductXmlCompletedEventArgs e){  // Store XML data in Isolated Storage  IsolatedStorageSettings.ApplicationSettings[KEY_NAME] = e.Result;   btnRead.IsEnabled = true;} As you can see, this is a fairly standard call to a WCF Service. In the Completed event you get the Result from the event argument, which is the XML, and store it into Isolated Storage using the IsolatedStorageSettings.ApplicationSettings class. Notice the constant that I added to specify the name of the key. You will use this constant later to read the data from Isolated Storage. Step 4: Create a Product Class Even though you stored XML data into Isolated Storage when you read that data out you will want to convert each element in the XML file into an actual Product object. This means that you need to create a Product class in your Windows Phone application. Add a Product class to your project that looks like the code below: public class Product{  public string ProductName{ get; set; }  public int ProductId{ get; set; }  public DateTime IntroductionDate{ get; set; }  public decimal Price{ get; set; }} Step 5: Read Settings from Isolated Storage Now that you have the XML data stored in Isolated Storage, it is time to use it. Go back to the MainPage.xaml design view and double click on the Read XML button to generate the Click event procedure. From the Click event procedure call a method named ReadProductXml().Create this method as shown below: private void ReadProductXml(){  XElement xElem = null;   if (IsolatedStorageSettings.ApplicationSettings.Contains(KEY_NAME))  {    xElem = XElement.Parse(     IsolatedStorageSettings.ApplicationSettings[KEY_NAME].ToString());     // Create a list of Product objects    var products =         from prod in xElem.Descendants("Product")        orderby prod.Attribute("ProductName").Value        select new Product        {          ProductId = Convert.ToInt32(prod.Attribute("ProductId").Value),          ProductName = prod.Attribute("ProductName").Value,          IntroductionDate =             Convert.ToDateTime(prod.Attribute("IntroductionDate").Value),          Price = Convert.ToDecimal(prod.Attribute("Price").Value)        };     lstData.DataContext = products;  }} The ReadProductXml() method checks to make sure that the key name that you saved your XML as exists in Isolated Storage prior to trying to open it. If the key name exists, then you retrieve the value as a string. Use the XElement’s Parse method to convert the XML string to a XElement object. LINQ to XML is used to iterate over each element in the XElement object and create a new Product object from each attribute in your XML file. The LINQ to XML code also orders the XML data by the ProductName. After the LINQ to XML code runs you end up with an IEnumerable collection of Product objects in the variable named “products”. You assign this collection of product data to the DataContext of the ListBox you created in XAML. The DisplayMemberPath property of the ListBox is set to “ProductName” so it will now display the product name for each row in your products collection. Summary In this article you learned how to retrieve an XML string from a table in a database, return that string across a WCF Service and store it into Isolated Storage on your Windows Phone. You then used LINQ to XML to create a collection of Product objects from the data stored and display that data in a Windows Phone list box. This same technique can be used in Silverlight or WPF applications too. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "Get XML From Server for Use on Windows Phone" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.  

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  • .Net Rocks TV - Architecting Windows Phone Applications

    - by psheriff
    I recently completed a .NET Rocks TV show with Carl Franklin. In this episode I discuss some design decisions that will help you create architecturally sound Windows Phone applications. Of course, many of the techniques will also apply to Silverlight and WPF application development as well. Check out the episode at http://www.dnrtv.com/default.aspx?showNum=184   Good Luck with your Coding,Paul Sheriff   ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.

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  • Override ToString() in your Classes

    - by psheriff
    One of the reasons I love teaching is because of the questions that I get from attendees. I was giving a presentation at DevConnections and was showing a collection of Product objects. When I hovered over the variable that contained the collection, it looked like Figure 2. As you can see in the collection, I have actual product names of my videos from www.pdsa.com/videos being displayed. To get your data to appear in the data tips you must override the ToString() method in your class. To illustrate this, take the following simple Product class shown below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }} This class does not have an override of the ToString() method so if you create a collection of Product objects you will end up with data tips that look like Figure 1. Below is the code I used to create a collection of Product objects. I have shortened the code in this blog, but you can get the full source code for this sample by following the instructions at the bottom of this blog entry. List<Product> coll = new List<Product>();Product prod; prod = new Product()  { ProductName = "From Zero to HTML 5 in 60 Minutes",     ProductId = 1 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting Applications …",     ProductId = 2 };coll.Add(prod);prod = new Product()  { ProductName = "Introduction to Windows Phone Development",    ProductId = 3 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting a Business  …",     ProductId = 4 };coll.Add(prod);......   Figure 1: Class without overriding ToString() Now, go back to the Product class and add an override of the ToString() method as shown in the code listed below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }   public override string ToString()  {    return ProductName;  }} In this simple sample, I am just returning the ProductName property. However, you can create a whole string of information if you wish to display more data in your data tips. Just concatenate any properties you want from your class and return that string. When you now run the application and hover over the collection object you will now see something that looks like Figure 2. Figure 2: Overriding ToString() in your Class Another place the ToString() override comes in handy is if you forget to use a DisplayMemberPath in your ListBox or ComboBox. The ToString() method is called automatically when a class is bound to a list control. Summary You should always override the ToString() method in your classes as this will help you when debugging your application. Seeing relevant data immediately in the data tip without having to drill down one more layer and maybe scroll through a complete list of properties should help speed up your development process. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Override ToString” from the drop down list.  

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  • Copy New Files Only in .NET

    - by psheriff
    Recently I had a client that had a need to copy files from one folder to another. However, there was a process that was running that would dump new files into the original folder every minute or so. So, we needed to be able to copy over all the files one time, then also be able to go back a little later and grab just the new files. After looking into the System.IO namespace, none of the classes within here met my needs exactly. Of course I could build it out of the various File and Directory classes, but then I remembered back to my old DOS days (yes, I am that old!). The XCopy command in DOS (or the command prompt for you pure Windows people) is very powerful. One of the options you can pass to this command is to grab only newer files when copying from one folder to another. So instead of writing a ton of code I decided to simply call the XCopy command using the Process class in .NET. The command I needed to run at the command prompt looked like this: XCopy C:\Original\*.* D:\Backup\*.* /q /d /y What this command does is to copy all files from the Original folder on the C drive to the Backup folder on the D drive. The /q option says to do it quitely without repeating all the file names as it copies them. The /d option says to get any newer files it finds in the Original folder that are not in the Backup folder, or any files that have a newer date/time stamp. The /y option will automatically overwrite any existing files without prompting the user to press the "Y" key to overwrite the file. To translate this into code that we can call from our .NET programs, you can write the CopyFiles method presented below. C# using System.Diagnostics public void CopyFiles(string source, string destination){  ProcessStartInfo si = new ProcessStartInfo();  string args = @"{0}\*.* {1}\*.* /q /d /y";   args = string.Format(args, source, destination);   si.FileName = "xcopy";  si.Arguments = args;  Process.Start(si);} VB.NET Imports System.Diagnostics Public Sub CopyFiles(source As String, destination As String)  Dim si As New ProcessStartInfo()  Dim args As String = "{0}\*.* {1}\*.* /q /d /y"   args = String.Format(args, source, destination)   si.FileName = "xcopy"  si.Arguments = args  Process.Start(si)End Sub The CopyFiles method first creates a ProcessStartInfo object. This object is where you fill in name of the command you wish to run and also the arguments that you wish to pass to the command. I created a string with the arguments then filled in the source and destination folders using the string.Format() method. Finally you call the Start method of the Process class passing in the ProcessStartInfo object. That's all there is to calling any command in the operating system. Very simple, and much less code than it would have taken had I coded it using the various File and Directory classes. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.  

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  • DevConnections new "Fundamentals" Track!

    - by psheriff
    Hi All, I am now the new Track Chair for the "Fundamentals" track at DevConnections. I know many of my readers feel overwhelmed by all of the "advanced" topics out there. The folks at the DevConnections conference realized that too and have added many new sessions that help programmers that are in the beginning to intermediate stage get up to speed on all the new technology that is coming out so fast. I will be presenting a whole day long workshop at the DevConnections conference in Orlando on March 27th entitled "Essential Business Desktop Programming with .NET". In addition I will be presenting the following sessions in the Fundamentals Track. MVVM Made Simple Unit Testing Basics and Architecting Your Application for Unit Testing Data Binding from A-Z in Silverlight From Zero to Windows Phone 7 in 75 MinutesI hope I will see you there! Join me at DevConnections @devconnections in Orlando March 27-30.   Save $200 use discount code DevCon1 Register today at bit.ly/fIZjXO

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  • Sort Data in Windows Phone using Collection View Source

    - by psheriff
    When you write a Windows Phone application you will most likely consume data from a web service somewhere. If that service returns data to you in a sort order that you do not want, you have an easy alternative to sort the data without writing any C# or VB code. You use the built-in CollectionViewSource object in XAML to perform the sorting for you. This assumes that you can get the data into a collection that implements the IEnumerable or IList interfaces.For this example, I will be using a simple Product class with two properties, and a list of Product objects using the Generic List class. Try this out by creating a Product class as shown in the following code:public class Product {  public Product(int id, string name)   {    ProductId = id;    ProductName = name;  }  public int ProductId { get; set; }  public string ProductName { get; set; }}Create a collection class that initializes a property called DataCollection with some sample data as shown in the code below:public class Products : List<Product>{  public Products()  {    InitCollection();  }  public List<Product> DataCollection { get; set; }  List<Product> InitCollection()  {    DataCollection = new List<Product>();    DataCollection.Add(new Product(3,        "PDSA .NET Productivity Framework"));    DataCollection.Add(new Product(1,        "Haystack Code Generator for .NET"));    DataCollection.Add(new Product(2,        "Fundamentals of .NET eBook"));    return DataCollection;  }}Notice that the data added to the collection is not in any particular order. Create a Windows Phone page and add two XML namespaces to the Page.xmlns:scm="clr-namespace:System.ComponentModel;assembly=System.Windows"xmlns:local="clr-namespace:WPSortData"The 'local' namespace is an alias to the name of the project that you created (in this case WPSortData). The 'scm' namespace references the System.Windows.dll and is needed for the SortDescription class that you will use for sorting the data. Create a phone:PhoneApplicationPage.Resources section in your Windows Phone page that looks like the following:<phone:PhoneApplicationPage.Resources>  <local:Products x:Key="products" />  <CollectionViewSource x:Key="prodCollection"      Source="{Binding Source={StaticResource products},                       Path=DataCollection}">    <CollectionViewSource.SortDescriptions>      <scm:SortDescription PropertyName="ProductName"                           Direction="Ascending" />    </CollectionViewSource.SortDescriptions>  </CollectionViewSource></phone:PhoneApplicationPage.Resources>The first line of code in the resources section creates an instance of your Products class. The constructor of the Products class calls the InitCollection method which creates three Product objects and adds them to the DataCollection property of the Products class. Once the Products object is instantiated you now add a CollectionViewSource object in XAML using the Products object as the source of the data to this collection. A CollectionViewSource has a SortDescriptions collection that allows you to specify a set of SortDescription objects. Each object can set a PropertyName and a Direction property. As you see in the above code you set the PropertyName equal to the ProductName property of the Product object and tell it to sort in an Ascending direction.All you have to do now is to create a ListBox control and set its ItemsSource property to the CollectionViewSource object. The ListBox displays the data in sorted order by ProductName and you did not have to write any LINQ queries or write other code to sort the data!<ListBox    ItemsSource="{Binding Source={StaticResource prodCollection}}"   DisplayMemberPath="ProductName" />SummaryIn this blog post you learned that you can sort any data without having to change the source code of where the data comes from. Simply feed the data into a CollectionViewSource in XAML and set some sort descriptions in XAML and the rest is done for you! This comes in very handy when you are consuming data from a source where the data is given to you and you do not have control over the sorting.NOTE: You can download this article and many samples like the one shown in this blog entry at my website. http://www.pdsa.com/downloads. Select “Tips and Tricks”, then “Sort Data in Windows Phone using Collection View Source” from the drop down list.Good Luck with your Coding,Paul Sheriff** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • Get Application Title from Windows Phone

    - by psheriff
    In a Windows Phone application that I am currently developing I needed to be able to retrieve the Application Title of the phone application. You can set the Deployment Title in the Properties of your Windows Phone Application, however getting to this value programmatically can be a little tricky. This article assumes that you have Visual Studio 2010 and the Windows Phone tools installed along with it. The Windows Phone tools must be downloaded separately and installed with Visual Studio2010. You may also download the free Visual Studio2010 Express for Windows Phone developer environment. The WMAppManifest.xml File First off you need to understand that when you set the Deployment Title in the Properties windows of your Windows Phone application, this title actually gets stored into an XML file located under the \Properties folder of your application. This XML file is named WMAppManifest.xml. A portion of this file is shown in the following listing. <?xml version="1.0" encoding="utf-8"?><Deployment  http://schemas.microsoft.com/windowsphone/2009/deployment"http://schemas.microsoft.com/windowsphone/2009/deployment"  AppPlatformVersion="7.0">  <App xmlns=""       ProductID="{71d20842-9acc-4f2f-b0e0-8ef79842ea53}"       Title="Mobile Time Track"       RuntimeType="Silverlight"       Version="1.0.0.0"       Genre="apps.normal"       Author="PDSA, Inc."       Description="Mobile Time Track"       Publisher="PDSA, Inc."> ... ...  </App></Deployment> Notice the “Title” attribute in the <App> element in the above XML document. This is the value that gets set when you modify the Deployment Title in your Properties Window of your Phone project. The only value you can set from the Properties Window is the Title. All of the other attributes you see here must be set by going into the XML file and modifying them directly. Note that this information duplicates some of the information that you can also set from the Assembly Information… button in the Properties Window. Why Microsoft did not just use that information, I don’t know. Reading Attributes from WMAppManifest I searched all over the namespaces and classes within the Windows Phone DLLs and could not find a way to read the attributes within the <App> element. Thus, I had to resort to good old fashioned XML processing. First off I created a WinPhoneCommon class and added two static methods as shown in the snippet below: public class WinPhoneCommon{  /// <summary>  /// Returns the Application Title   /// from the WMAppManifest.xml file  /// </summary>  /// <returns>The application title</returns>  public static string GetApplicationTitle()  {    return GetWinPhoneAttribute("Title");  }   /// <summary>  /// Returns the Application Description   /// from the WMAppManifest.xml file  /// </summary>  /// <returns>The application description</returns>  public static string GetApplicationDescription()  {    return GetWinPhoneAttribute("Description");  }   ... GetWinPhoneAttribute method here ...} In your Windows Phone application you can now simply call WinPhoneCommon.GetApplicationTitle() or WinPhone.GetApplicationDescription() to retrieve the Title or Description properties from the WMAppManifest.xml file respectively. You notice that each of these methods makes a call to the GetWinPhoneAttribute method. This method is shown in the following code snippet: /// <summary>/// Gets an attribute from the Windows Phone WMAppManifest.xml file/// To use this method, add a reference to the System.Xml.Linq DLL/// </summary>/// <param name="attributeName">The attribute to read</param>/// <returns>The Attribute's Value</returns>private static string GetWinPhoneAttribute(string attributeName){  string ret = string.Empty;   try  {    XElement xe = XElement.Load("WMAppManifest.xml");    var attr = (from manifest in xe.Descendants("App")                select manifest).SingleOrDefault();    if (attr != null)      ret = attr.Attribute(attributeName).Value;  }  catch  {    // Ignore errors in case this method is called    // from design time in VS.NET  }   return ret;} I love using the new LINQ to XML classes contained in the System.Xml.Linq.dll. When I did a Bing search the only samples I found for reading attribute information from WMAppManifest.xml used either an XmlReader or XmlReaderSettings objects. These are fine and work, but involve a little extra code. Instead of using these, I added a reference to the System.Xml.Linq.dll, then added two using statements to the top of the WinPhoneCommon class: using System.Linq;using System.Xml.Linq; Now, with just a few lines of LINQ to XML code you can read to the App element and extract the appropriate attribute that you pass into the GetWinPhoneAttribute method. Notice that I added a little bit of exception handling code in this method. I ignore the exception in case you call this method in the Loaded event of a user control. In design-time you cannot access the WMAppManifest file and thus an exception would be thrown. Summary In this article you learned how to retrieve the attributes from the WMAppManifest.xml file. I use this technique to grab information that I would otherwise have to hard-code in my application. Getting the Title or Description for your Windows Phone application is easy with just a little bit of LINQ to XML code. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "Get Application Title from Windows Phone" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.  

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  • A WPF Image/Text Button

    - by psheriff
    Some of our customers are asking us to give them a Windows 8 look and feel for their applications. This includes things like buttons, tiles, application bars, and other features. In this blog post I will describe how to create a button that looks similar to those you will find in a Windows 8 application bar. In Figure 1 you can see two different kinds of buttons. In the top row is a WPF button where the content of the button includes a Border, an Image and a TextBlock. In the bottom row are four...(read more)

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  • Creating a XAML Tile Control

    - by psheriff
    One of the navigation mechanisms used in Windows 8 and Windows Phone is a Tile. A tile is a large rectangle that can have words and pictures that a user can click on. You can build your own version of a Tile in your WPF or Silverlight applications using a User Control. With just a little bit of XAML and a little bit of code-behind you can create a navigation system like that shown in Figure 1. Figure 1: Use a Tile for navigation. You can build a Tile User Control with just a little bit of XAML and...(read more)

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