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  • What's the order of execution in property setters when using IDataErrorInfo?

    - by Benny Jobigan
    Situation: Many times with WPF, we use INotifyPropertyChanged and IDataErrorInfo to enable binding and validation on our data objects. I've got a lot of properties that look like this: public SomeObject SomeData { get { return _SomeData; } set { _SomeData = value; OnPropertyChanged("SomeData"); } } Of course, I have an appropriate overridden IDataErrorInfo.this[] in my class to do validation. Question: In a binding situation, when does the validation code get executed? When is the property set? When is the setter code executed? What if the validation fails? For example: User enters new data. Binding writes data to property. Property set method is executed. Binding checks this[] for validation. If the data is invalid, the binding sets the property back to the old value. Property set method is executed again. This is important if you are adding "hooks" into the set method, like: public string PathToFile { get { return _PathToFile; } set { if (_PathToFile != value && // prevent unnecessary actions OnPathToFileChanging(value)) // allow subclasses to do something or stop the setter { _PathToFile = value; OnPathToFileChanged(); // allow subclasses to do something afterwards OnPropertyChanged("PathToFile"); } } }

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  • wpf observableCollection

    - by Asha
    I have an ObservableCollection which is dataContext for my treeview when I try to remove an Item from ObservableCollection I will get an error that Object reference not set to an instance of an object . can you please tell me why this error is happening and what is the solution thanks EDIT 1: The code is something like : class MyClass : INotifyPropertyChanged { //my class code here } public partial class UC_myUserControl : UserControl { private ObservableCollection<MyClass> myCollection = new ObservableCollection<MyClass>(); private void UserControl_Loaded(object sender, RoutedEventArgs e) { myCollection.add(new myClass); myTreeView.DataContext = myCollection ; } private void deleteItem() { myCollection.RemoveAt(0); //after removing I get error Which I guess should be something related //to interface update but I don't know how can I solve it } } Exception Detail : System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="PresentationFramework" EDIT 3: I have a style which is for my treeitem to keep the treeitems expanded <Style TargetType="TreeViewItem"> <Setter Property="IsExpanded" Value="True" /> </Style> and with commenting this part I wont get any error !!! Now I want to change my question to why having this style is causing error ?

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  • how to insert an integer value from a Grid to Sql table?

    - by z-chaos
    Hi, I have a AdvWebGrid where the 7th coloumn is DynEdit where user will enter the value.Now I have to take the enetered value and insert into the Sql tablel. For example i have 7 records in the grid the user will enter some comments for the first three record and save.Now i have to insert/update the first three comments in the table.

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  • web service filling gridview awfully slow, as is paging/sorting

    - by nat
    Hi I am making a page which calls a web service to fill a gridview this is returning alot of data, and is horribly slow. i ran the svcutil.exe on the wsdl page and it generated me the class and config so i have a load of strongly typed objects coming back from each request to the many service functions. i am then using LINQ to loop around the objects grabbing the necessary information as i go, but for each row in the grid i need to loop around an object, and grab another list of objects (from the same request) and loop around each of them.. 1 to many parent object child one.. all of this then gets dropped into a custom datatable a row at a time.. hope that makes sense.... im not sure there is any way to speed up the initial load. but surely i should be able to page/sort alot faster than it is doing. as at the moment, it appears to be taking as long to page/sort as it is to load initially. i thought if when i first loaded i put the datasource of the grid in the session, that i could whip it out of the session to deal with paging/sorting and the like. basically it is doing the below protected void Page_Load(object sender, EventArgs e) { //init the datatable //grab the filter vars (if there are any) WebServiceObj WS = WSClient.Method(args); //fill the datatable (around and around we go) foreach (ParentObject po in WS.ReturnedObj) { var COs = from ChildObject c in WS.AnotherReturnedObj where c.whatever.equals(...) ...etc foreach(ChildObject c in COs){ myDataTable.Rows.Add(tlo.this, tlo.that, c.thisthing, c.thatthing, etc......); } } grdListing.DataSource = myDataTable; Session["dt"] = myDataTable; grdListing.DataBind(); } protected void Listing_PageIndexChanging(object sender, GridViewPageEventArgs e) { grdListing.PageIndex = e.NewPageIndex; grdListing.DataSource = Session["dt"] as DataTable; grdListing.DataBind(); } protected void Listing_Sorting(object sender, GridViewSortEventArgs e) { DataTable dt = Session["dt"] as DataTable; DataView dv = new DataView(dt); string sortDirection = " ASC"; if (e.SortDirection == SortDirection.Descending) sortDirection = " DESC"; dv.Sort = e.SortExpression + sortDirection; grdListing.DataSource = dv.ToTable(); grdListing.DataBind(); } am i doing this totally wrongly? or is the slowness just coming from the amount of data being bound in/return from the Web Service.. there are maybe 15 columns(ish) and a whole load of rows.. with more being added to the data the webservice is querying from all the time any suggestions / tips happily received thanks

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  • How do I initialize the controls in an InsertItemTemplate?

    - by Slauma
    I have - for instance - an asp:FormView which supports Read, Insert, Update, Delete and is bound to a DataSource: <asp:FormView ID="FormView1" runat="server" DataSourceID="ObjectDataSource1" > <ItemTemplate> <asp:Label ID="Label1" runat="server" Text='<%# Bind("MyText") %>' /> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("MyText") %>' /> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("MyText") %>' /> </InsertItemTemplate> </asp:FormView> If I am in Read-Mode or Edit-Mode the control is initialized with the property MyText of the current object which is bound to the FormView. But when I go to Insert-Mode I do not have a "current object" (FormView1.DataItem is indeed null) and the controls are empty. If I want to have my TextBox control initialized with a specific value how can I do that? In which event can I hook in to set default values to the controls in the InsertItemTemplate? Especially I have in mind using an ObjectDataSource. I was expecting that the InsertItemTemplate is initialized with a business object which underlies my ObjectDataSource and which is created by the ASP.NET framework simply by using its default constructor when the InsertItemTemplate gets activated. In the default constructor I would init the class members to the default values I'd like to have in my controls of the InsertItemTemplate. But unfortunately that's not the case: No "default" object is created and bound to the FormView. So it seems I have to initialize all controls separately or to create the default object manually and bind it to the InsertItemTemplate of the FormView. But how and where can I do that? Thanks in advance!

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  • How to make a cell in a datagrid readonly based the content on another cell in SL4?

    - by Nair
    I have two columns, the second column depends on the content on the first column. By default, the second columns is readonly. When I enter some valid value, I want the second column to become editable. To achive this, I created a cell template and cell edit template on the second column where back ground and read only bound to the first column. On load, the first column is null so my second columns comes correctly as read only. Following is Cell Template for second column, where the background color is set by based on the first column. <DataTemplate> <Grid> <Border Background="{Binding FristColumn,Converter={StaticResource ColorConverter}}"/> <TextBlock Text="{Binding SecondColumn, Converter={StaticResource NumberFormatter}}" HorizontalAlignment="Stretch" VerticalAlignment="Center" Margin="0"/> </Grid> </DataTemplate> Following is cell edit template for second column to make it editable <DataTemplate> <Grid> <TextBox Text="{Binding SecondColumn, Mode=TwoWay, Converter={StaticResource NumberFormatter}}" Margin="0" HorizontalAlignment="Right" IsReadOnly="{Binding FirstColumn, Converter={StaticResource readOnlyConverter}, ConverterParameter=FirstColumn}" Background="{Binding Depend,Converter={StaticResource ColorConverter}, ConverterParameter=FirstColumn}" /> </Grid> </DataTemplate> With these two in place, when enter the valid value in the first column, I was expecting the second column color to change but it does not. But If I double click on the cell then it behaves properly based on the first cell. Is there some thing I am missing?

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  • WPF XAML: How to trigger style change in ListBoxItem ancestor to user class?

    - by dhovel
    I have an ObservableCollection of items of my class "PlaylistItem" that implements INotifyPropertyChanged. The collection is databound to a ListBox and everything else is working. I want to know what markup to use to trigger a style change of the wrapping ListBoxItem based on a property (e.g. "Playing", bool) of the PlaylistItem. How to I use FindAncestor to trigger the change? I can to this in code, but I know I that I can (somehow) do it in markup. Thanks in advance.

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  • Silverlight dataGrid binding with ria Service doesn' work

    - by Abdulrhman
    hi every one i'm new to Silverlight and it's totally driving me crazy !! i'm using SL4 and trying to bind datagrid with a Domain Service Query: what i did exactly is i generate an ado.net entity model from my database, then create a domain Service class from this model. then in my page i put Datagrid & button. in the click event for this button i write this code: RRDomainContext rr = new RRDomainContext(); this.dataGrid1.ItemsSource = rr.Rooms; this.rr.Load(this.rr.GetRoomsQuery()); when this method executed the nothing changed at the datagrid. can anyone help me with this ?

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  • WPF update binding in a background thread

    - by Mark
    I have a control that has its data bound to a standard ObservableCollection, and I have a background task that calls a service to get more data. I want to, then, update my backing data behind my control, while displaying a "please wait" dialog, but when I add the new items to the collection, the UI thread locks up while it re-binds and updates my controls. Can I get around this so that my animations and stuff keep running on my "please wait" dialog? Or at least give the "appearance" to the user that its not locked up?

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  • WPF ComboBox drop-down (data bound) values not changing

    - by Jefim
    I bind the ItemsSource of a ComboBox to an ObservableCollection<MyClass>. In code I change the collection (e.g. edit the MyClass.Name property). The problem: the change is not reflected in the dropdown box if the ComboBox, yet when I seled the item from the dropdown it is displayed correctly in the selected item box of the ComboBox. What's going on? :) PS MyClass has INotifyPropertyChanged implemented

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  • Get invalid user input with a Spring typeMismatch error

    - by TimmyJ
    I've implemented a ReloadableResourceBundleMessageSource in my Spring MVC application which I use to display prettier error messages for binding exceptions. The problem I'm having is that, due to a company policy, these errors must be displayed in the following format: [inputData] is not a valid [fieldName]. The field name is accessible by default in my message properties file (as the {0} argument), but I can't figure out a way to display the invalid user input. Is this possible?

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  • Combobox INotifyPropertyChanged event not raised!!!

    - by nagiah
    I created a combobox and set observable collection as the itemsource and implemented INotifyPropertyChanged on the observable collection item. Even after that, when I select different item in the combobox, the OnPropertyChange method is not invoked. I think I am not making the binding properly. Could any one please correct me/ suggest me in this regard. ---------------------------------MainPage.xaml--------------------------------------------------- <StackPanel Width="300"> <ComboBox Name="cboName"></ComboBox> <TextBox Name="tbxName" Text="{Binding Path=name,Mode=TwoWay,ElementName=cboName}" ></TextBox> </StackPanel> ---------------------------MainPage.xaml.cs----------------------------------------------- using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Collections.ObjectModel; using System.Collections.Specialized; using System.ComponentModel; namespace MasterDetailsUpdate { public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); Loaded += new RoutedEventHandler(MainPage_Loaded); } void MainPage_Loaded(object sender, RoutedEventArgs e) { ObservableCollection<Person> persons = new ObservableCollection<Person>(); persons.Add(new Person { city = "c1", name = "n1" }); persons.Add(new Person { city = "c2", name = "n2" }); persons.Add(new Person { city = "c3", name = "" }); persons.Add(new Person { city = "c4", name = "" }); persons.Add(new Person { city = "c5", name = "n1" }); cboName.ItemsSource = persons; cboName.DisplayMemberPath = "name"; } } public class Person : INotifyPropertyChanged { private string _name; private string _city; public string name { set { _name = value; OnPropertyChanged("name"); } get { return _name; } } public string city { set { _city = value; OnPropertyChanged("city"); } get { return _city; } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } #endregion } } Thank You

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  • How can i bind parent's property to its child's property?

    - by walkor
    I have a GroupBox, which is defined like this <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:Groupbox" > <Style TargetType="local:GroupBox"> <Setter Property="BorderBrush" Value="DarkGray"/> <Setter Property="BorderThickness" Value="1"/> <Setter Property="Padding" Value="6"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="local:GroupBox"> <Grid Background="{TemplateBinding Background}"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Border BorderThickness="{TemplateBinding BorderThickness}" Grid.Row="1" Grid.RowSpan="2" BorderBrush="{TemplateBinding BorderBrush}" CornerRadius="3"> <Border.Clip> <GeometryGroup FillRule="EvenOdd"> <RectangleGeometry x:Name="FullRect" Rect="0,0,300,200"/> <RectangleGeometry x:Name="HeaderRect" Rect="6,0,100,100"/> </GeometryGroup> </Border.Clip> </Border> <ContentPresenter Grid.Row="2" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Margin="{TemplateBinding Padding}"/> <ContentControl x:Name="HeaderContainer" Margin="6,0,0,0" Grid.Row="0" Grid.RowSpan="2" HorizontalAlignment="Left"> <ContentPresenter Margin="3,0,3,0" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}"/> </ContentControl> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary> And i'm using this control like this <Controls:GroupBox x:Name="GroupBox"> <Controls:GroupBox.HeaderTemplate> <DataTemplate> <CheckBox "Header" x:Name="cbHeader"/> </DataTemplate> </Controls:GroupBox.HeaderTemplate> <Controls:GroupBox> So, well, my questions - how can i bind property IsEnabled of GroupBox to the Checkbox property IsChecked? Thanks in advance.

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  • How to cause bindings to be updated, particularly for derived values?

    - by rrhartjr
    I'm using some CLR objects that use the INotifyPropertyChanged interface and use the PropertyChanged function to update in WPF bindings. Pretty boilerplate: protected void RaisePropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } Then the property: private double m_TotalWidgets = 0; public double TotalWidgets { get { return m_TotalWidgets; } set { m_TotalWidgets = value; RaisePropertyChanged("TotalWidgets"); } } Is there a better way to update a derived value or even the whole class? Say I had a calculated value: public double ScaledWidgets { get { return TotalWidgets * CONSTANT_FACTOR; } } I would have to fire ScaledWidget's PropertyChanged when TotalWidgets is updated, eg: set { m_TotalWidgets = value; RaisePropertyChanged("TotalWidgets"); RaisePropertyChanged("ScaledWidgets"); } Is there a better way to do this? Is it possible "invalidate" the whole object, especially if there are a lot of derived values? I think it would be kind of lame to fire 100 PropertyChanged events.

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  • WPF - Get combobox checked property from ListBox

    - by Chris Klepeis
    I have a listbox, which is defined like so: <ListBox ItemsSource="{Binding Source={x:Static local:ResourceCollection.resourceList}}" Height="143" HorizontalAlignment="Left" Margin="6,6,0,0" Name="assignmentLB" VerticalAlignment="Top" Width="287" FontSize="12" FontWeight="Normal" IsEnabled="True" Grid.Column="0"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <CheckBox /> <TextBlock Text="{Binding Content}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> How can I loop through this listbox and retrieve the TextBlock.Text value for only items whose Checkbox has been checked?

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  • updating dataset using join and bindingsource?

    - by netadictos
    Hi, I have created a dataset and in the designer I have created the relations and foreign keys that exist in the database. Basically, I have a product that has a relationship to a table of prices. The keyfield they share is IdProduct in the Prices table. In the Fill/Get of the product I return the Price field. I also have a DataGrid that uses a BindingSource which uses this table. Everything displays correctly and when I double click on a row within the datagrid I then open up a tabbed form that contains a detailed view of the record selected. The user at this point is able to make changes to the record and they are properly propogated back to the BindingSource. The problem is that the TableAdapter does not contain the appopriate update, therefore I am not able to call the TableAdapter.Update method with the dataset as I would had I created a tableadapter not using a join. How am I best to handle this situation. At the same time I cannot get any modified row: dTiendasDs.ProductosDataTable modified = (dTiendasDs.ProductosDataTable) dTiendasDs.Productos.GetChanges(DataRowState.Modified); modified is always null Thanks,

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  • Binding ComboBoxes to enums... in Silverlight!

    - by Domenic
    So, the web, and StackOverflow, have plenty of nice answers for how to bind a combobox to an enum property in WPF. But Silverlight is missing all of the features that make this possible :(. For example: You can't use a generic EnumDisplayer-style IValueConverter that accepts a type parameter, since Silverlight doesn't support x:Type. You can't use ObjectDataProvider, like in this approach, since it doesn't exist in Silverlight. You can't use a custom markup extension like in the comments on the link from #2, since markup extensions don't exist in Silverlight. You can't do a version of #1 using generics instead of Type properties of the object, since generics aren't supported in XAML (and the hacks to make them work all depend on markup extensions, not supported in Silverlight). Massive fail! As I see it, the only way to make this work is to either Cheat and bind to a string property in my ViewModel, whose setter/getter does the conversion, loading values into the ComboBox using code-behind in the View. Make a custom IValueConverter for every enum I want to bind to. Are there any alternatives that are more generic, i.e. don't involve writing the same code over and over for every enum I want? I suppose I could do solution #2 using a generic class accepting the enum as a type parameter, and then create new classes for every enum I want that are simply class MyEnumConverter : GenericEnumConverter<MyEnum> {} What are your thoughts, guys?

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  • fix a columns width when a list is bound to a datagridview

    - by Andy
    I have a list that I have bound to a datagridview. I want the first column to be a fixed size. The data is bound to the dataGridView and I can't seem to find a way to access an individual colums properties. if I try myDatagridview.colums[0] I get an index out of bounds, since it says the columns count is 0. private DataGridView setUpDataGrid(List<NVRlineVal> _NVRData) { //setup dataGridView DataGridView NVRDataGridView = new System.Windows.Forms.DataGridView(); NVRDataGridView.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize; NVRDataGridView.Dock = System.Windows.Forms.DockStyle.Fill; NVRDataGridView.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill; NVRDataGridView.Location = new System.Drawing.Point(3, 3); NVRDataGridView.Name = "NVRDataGridView" + nvrIndex; NVRDataGridView.RowHeadersWidthSizeMode = System.Windows.Forms.DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders; NVRDataGridView.Size = new System.Drawing.Size(380, 401); NVRDataGridView.TabIndex = 0; NVRDataGridView.DataSource = _NVRData; var test = NVRDataGridView.Columns; NVRDataGridView.DataMember = "devState"; DataGridViewAutoSizeColumnMode.None; } Any ideas on how to have a fixed column width for only one of these columns, the rest will autosize?

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  • ASP:DropDownList in ItemTemplate: Why is SelectedValue attribute allowed?

    - by recursive
    This piece of code <asp:DropDownList runat="server" ID="testdropdown" SelectedValue="2"> <asp:ListItem Text="1" Value="1"></asp:ListItem> <asp:ListItem Text="2" Value="2"></asp:ListItem> <asp:ListItem Text="3" Value="3"></asp:ListItem> </asp:DropDownList> yields this error: The 'SelectedValue' property cannot be set declaratively. Yet, this is a legal and commonly used edit template for databound GridViews. The SelectedValue attribute certainly appears to be declaratively set here. <EditItemTemplate> <asp:DropDownList runat="server" ID="GenreDropDownList" DataSourceID="GenreDataSource" DataValueField="GenreId" DataTextField="Name" SelectedValue='<%# Bind("Genre.GenreId") %>'> </asp:DropDownList> </EditItemTemplate> The question is: what is the difference between the cases when you are allowed to set it declaratively and those in which you are not? The error message implies that it's never allowed.

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  • WPF data-bound ComboBox only shows first item of ItemsSource list

    - by Mark
    Hi all, I'm sure I'm doing something stupid but for the life of me I can't think of right now. I have a ComboBox that is data-bound to a list of Layout objects. The list is initially empty but things are added over time. When the list is updated by the model the first time, this update reflects properly in the ComboBox. However, subsequent updates never show up in the ComboBox even though I can see that the list itself contains these items. Since the first update works, I know the data-binding is OK - so what am I doing wrong here? Here's the XAML (abridged): <Grid HorizontalAlignment="Stretch"> <ComboBox ItemsSource="{Binding Path=SavedLayouts, diagnostics:PresentationTraceSources.TraceLevel=High}" DisplayMemberPath="Name" SelectedValuePath="Name" SelectedItem="{Binding LoadLayout}" Height="25" Grid.Row="1" Grid.Column="0"></ComboBox> </Grid> And the related part of the model: public IList<Layout> SavedLayouts { get { return _layouts; } } public Layout SaveLayout( String data_ ) { Layout theLayout = new Layout( SaveLayoutName ); _layouts.Add( theLayout ); try { return theLayout; } finally { PropertyChangedEventHandler handler = PropertyChanged; if( handler != null ) { handler( this, new PropertyChangedEventArgs( "SavedLayouts" ) ); } } } And finally, the layout class (abridged): public class Layout { public String Name { get; private set; } } In the output window, I can see the update occurring: System.Windows.Data Warning: 91 : BindingExpression (hash=64564967): Got PropertyChanged event from TickerzModel (hash=43624632) System.Windows.Data Warning: 97 : BindingExpression (hash=64564967): GetValue at level 0 from TickerzModel (hash=43624632) using RuntimePropertyInfo(SavedLayouts): List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 76 : BindingExpression (hash=64564967): TransferValue - got raw value List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 85 : BindingExpression (hash=64564967): TransferValue - using final value List`1 (hash=16951421 Count=11) But I get do not get this 11th item in the ComboBox. Any ideas?

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  • database text field databound to a checkbox

    - by Patrick
    I'd like the field to save as a 1 or 0 instead of 'True' or 'False' in the database and i cannot figure out how to do it without manually setting every property when the record is saved. I have to use this a lot in this project and a bit field is not an option. I would like to solve this issue by extending the CheckBox control if possible but i don't know how to change the binding fields value. Any help would be greatly appreciated!

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