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  • Win a Free Copy of Windows Presentation Foundation 4.5 Cookbook

    - by Ricardo Peres
    Win A free copy of the 'Windows Presentation Foundation 4.5 Cookbook', just by commenting! For the contest, Packt Publishing has two eBook copies of Windows Presentation Foundation 4.5 Cookbookto be given away to two lucky winners. How you can win: To win your copy of this book, all you need to do is come up with a comment below highlighting the reason "why you would like to win this book”. Duration of the contest & selection of winners: The contest is valid for 7 days (until November 26), and is open to everyone. Winners will be selected on the basis of their comment posted. Windows Presentation Foundation 4.5 Cookbookis written by Pavel Yosifovich, the CTO of CodeValue (http://www.codevalue.net), a software development, consulting, and training company, based in Israel. This book is written in an easy-to-read style, with a strong emphasis on real-world, practical examples. Step-by-step explanations are provided for performing important tasks. This book is the best guide for C# developer who is looking forward to increase understanding and knowledge of WPF. Using this book, readers will learn to build complex and flexible user interfaces using XAML, perform lengthy operations asynchronously while keeping the UI responsive, get well-versed with WPF features such as data binding, layout, resources, templates, and styles and also customize a control’s template to alter appearance but preserve behavior. In the next days I will post my review on this book. In the meantime, here’s the table of contents: Preface Chapter 1: Foundations Chapter 2: Resources Chapter 3: Layout and Panels Chapter 4: Using Standard Controls Chapter 5: Application and Windows Chapter 6: Data Binding Chapter 7: Commands and MVVM Chapter 8: Styles, Triggers, and Control Templates Chapter 9: Graphics and Animation Chapter 10: Custom Elements Chapter 11: Threading Index I’m waiting for your comments!

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  • Building applications with WPF, MVVM and Prism(aka CAG)

    - by skjagini
    In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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  • Binding ListBox to List (Collection) in XAML

    - by david2tm
    Hello, I'm learning WPF, so I'm kind of n00b in this. I saw some examples about how to do what I want to do, but nothing exactly... The question: I want to bind List to ListBox. I want to do it in XAML, w/o coding in code behind. How can I achieve that? Right now I do it that way: <!-- XAML --> <ListBox x:Name="FileList"> <ListBox.ItemTemplate> <DataTemplate> <Label Content="{Binding Path=.}"/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> // Code behind public MainWindow() { // ... files = new List<string>(); FileList.ItemsSource = files; } private void FolderBrowser_TextChanged(object sender, RoutedEventArgs e) { string folder = FolderBrowser.Text; files.Clear(); files.AddRange(Directory.GetFiles(folder, "*.txt", SearchOption.AllDirectories)); FileList.Items.Refresh(); } But I want to get rid of FileList.ItemsSource = files; and FileList.Items.Refresh(); in C# code. Thanks

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  • C#/WPF - RoutedEvent in WPF class that isn't a UIElement

    - by Andreas
    I have a class that needs to notify that something significant has occured. The class is in a WPF-project, even though this specific class, is lookless (and doesn't inherit from UIElement, neither directly or indirectly). Normally, I just register a RoutedEvent to get this functionality but as this class neither has AddHandler nor RemoveHandler, I can't get it to work. Anyone knows of another way of get the RoutedEvent behaviour?

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  • Query on MVVM pattern in WPF?

    - by Ashish Ashu
    I am implementing a MVVM pattern in my WPF application. My application main window is divided into four parts: Main Menu On the Top Outlook Navigation Control on the Left. A List View on the Middle. Another List view on the bottom. The Navigation control shows different setting (configuration) controls in the Tab items. All the four above are user controls which are placed in the main window. And corresponding to each user control there is separate view model which is bounded with a view model in the XAML of each control, however the model class remain the same between all the view model. And a MainWindow has a seperate View Model which is also bounded with a view model in the XAML of each control. Please help me out in framing a design in which each view models of all the controls above will interact with each other. Please let me know if my question is not clear to you!!

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  • WPF Window Style not working at runtime

    - by Christian Pena
    Hi, I created a WPF application in Visual Studio 2010 Express (C#) and added the text below to the Application.Resources in App.xaml. I see the style applied to the window in the designer, but when I run the application, the window background is white. Running in Windows XP on BootCamp on a MacBook Pro if that is a factor. Thanks in advance, Christian <Style TargetType="{x:Type Window}"> <Setter Property="Background"> <Setter.Value> <LinearGradientBrush StartPoint="0,0" EndPoint="0,1"> <GradientStop Offset="0" Color="WhiteSmoke" /> <GradientStop Offset="1" Color="Silver" /> </LinearGradientBrush> </Setter.Value> </Setter> <Setter Property="Padding" Value="20" /> </Style>

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  • WPF 3D - converting from Point2D to Point3D and back again

    - by DanM
    I'm new to WPF 3D, so I may just be missing something obvious, but how would I go about converting from a 2D coordinate to a 3D coordinate and back again? I'd like the 2D coordinate to be the location measured from the upper-left corner of Viewport3D and the 3D coordinate to be the location relative to the origin (0, 0, 0) of the 3D world. The conversion functions should have these signatures: public Point3D Point2DAndWorldZToPoint3D(Point2D point2D, double worldZ) // usually I want to know where a 2D point will be on the ground plane // so worldZ will usually be zero (but not always) public Point2D Point3DToPoint2D(Point3D point3D) I found this related question, but it only addresses conversion from 3D to 2D (not the reverse), and I'm not sure if the answers are up-to-date. Note, I'm currently using .NET 3.5, but if there are improvements in .NET 4.0 that would help me, please let me know.

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  • EventTrigger RoutedEvent in wpf xaml

    - by Cinaird
    I have a problem in wpf xaml and i'm pretty new on this so it may be something basic i want to rotate a ellipse 360 degree <Ellipse Name="test" Fill="Black" StrokeThickness="5" Margin="0,0,0,0" Height="66"> <Ellipse.Triggers> <EventTrigger RoutedEvent="Ellipse.Loaded" SourceName="test"> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetName="test" Storyboard.TargetProperty="(Ellipse.RenderTransform).(RotateTransform.Angle)" From="0" To="360" Duration="0:0:0.5" RepeatBehavior="1x" /> </Storyboard> </BeginStoryboard> </EventTrigger> </Ellipse.Triggers> </Ellipse> But nothing happens, what is wrong?

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  • WPF 3D - Need help writing conversion methods between 2D and 3D (Point3DToPoint and PointAndZToPoint

    - by DanM
    I'm new to WPF 3D, so I may just be missing something obvious, but how do I convert from 3D to 2D and (for a given z location) from 2D to 3D? Specifically, I need two conversion methods: Point3DToPoint - If I have an (x, y, z) coordinate in the 3D world, how do I determine the (x, y) coordinate on the projected 2D surface. Method signature: public Point Point3DToPoint(Point3D point3D) PointAndZToPoint3D - If I have an (x, y) coordinate on the projected 2D surface and a z location in the 3D world, how do I determine the intersecting (x, y, z) coordinate in the 3D world? Method signature: public Point3D PointAndZToPoint3D(Point point, double z) I'd like the 2D coordinate to be the location measured from the upper-left corner of Viewport3D and the 3D coordinate to be the location relative to the origin (0, 0, 0) of the 3D world. Note 1: I found this related question, but it only addresses conversion from 3D to 2D (not the reverse), and I'm not sure if the answers are up-to-date. Note 2: I'm currently using .NET 3.5, but if there are improvements in .NET 4.0 that would help me, please let me know.

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  • wpf toolkit (Feb 2010) datagrid with MVVM - style reveals name of view model on 'spare column'

    - by Andy Clarke
    Hi, I've just updated my app with the latest WPF toolkit and I've now got an issue with my styling. When I bind some data with, for example, two columns to the grid, the spare area at the right shows the name of the ViewModel in the header. I can understand why, because the data grids data context is the ViewModel and I'm defining my header style as follows ... <WpfToolkit:DataGridHeaderBorder <Border BorderBrush="Blue" BorderThickness="0,1,0,0"> <TextBlock Text="{Binding}" Margin="4,0,4,0" /> </Border> </WpfToolkit:DataGridHeaderBorder> Do I now need a separate style for the 'spare column' or something? Can anyone assist please? Cheers, Andy

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  • WPF Hide DataGridColumn via a binding

    - by Greg R
    For some reason I can't hide WPF Toolkit's DataGridColumn. I am trying to do the following: <dg:DataGridTemplateColumn Header="Item Description" Visibility="{Binding IsReadOnly}"> <dg:DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBox Text="{Binding Path=ItemDescription}" /> </DataTemplate> </dg:DataGridTemplateColumn.CellTemplate> This doesn't work, since it's looking for a IsReadOnly property on the ItemSource (not a property of the current class). If add this as a property of the ItemSource class that implements INoifyPropertyChanged, it still doesn't hide the column. Is there a way around this? I want the column to hid when a button click changes IsReadOnly property. Assume IsReadOnly returns a Visibility value and is a dependency property I am completely stuck, I would really appreciate the help! Thanks a lot!

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  • WPF MenuItem ViewModel Command

    - by Jon Archway
    Hi, I am fairly new to WPF and am struggling a little with a scenario. I have a menu which has menu items. When one of these menu items gets clicked a method needs to be called that will do something based upon the text displayed associated with that menu item. So for example, the menu item's content was "test" so I would need to do something with "test". FYI, this "something" directly affects a collection on the ViewModel. This is easy to achieve using the click event and no ViewModel, but I was trying to implement MVVM using an explicit ViewModel. So I started to look into Commands but cannot see how I would pass anything from the View back into the Command in the ViewModel. Any suggestions on what I should be doing here? Thanks

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  • WPF - Have a list source defined at runtime but still have sample data for design time

    - by Vaccano
    I have some ListBoxes in my WPF app. I would like to be able to view how the design looks with out having to run the app. But I still want to be able to bind to ItemsSource to my View Model. I know I saw a blog post on how to do this, but I cannot seem to find it now. To reiterate, I want dummy data at design time, but real data at run time and not break the MVVM pattern. Any ideas?

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  • How to Animate a Gradient on a Path to visualize data flow in WPF/WCF app

    - by John
    I have an interesting project where several "nodes" on a cnavas are connected via a Path similiar to a mindmap tree. The path is used to visualize the connection state between two nodes. Red means the nodes are disconnected, green means they're connected. The next step would be to illustrate data flow (from A to B or B to A) using that path and an animation. Basically I would want to start the animation with the data transfer and stop it when the transfer is complete. Does anyone know how this could be done in WPF?

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  • Navigate between screens in WPF

    - by Greg R
    This should be a very basic design question, but for some reason it doesn't seem to be well documented (maybe due to its simplicity?). If I'm building a dashboard application in WPF that brig up different CRM tasks and I want to navigate between screens, is this the best way to do this, or is there a better way? So for example I have Log In Screen - Main Menu Screen - Screen to one of different utilities var orderManagerWindow = new MyXamlView(); var loginWindow = Application.Current.MainWindow; orderManagerWindow.Left = loginWindow.Left; orderManagerWindow.Top = loginWindow.Top; Application.Current.MainWindow = orderManagerWindow; orderManagerWindow.Show(); loginWindow.Close(); I would really appreciate help and suggestions!

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  • Setting the background color of WPF TabControl inactive tabs

    - by David Veeneman
    Is there a simple way to set the background brush of all inactive tabs in a WPF TabControl? I want to emulate the look of VS 2010 on a TabControl--the background color of the control's inactive tabs should match the background color of the window in which the TabControl is sited, so that you see only the text of the tab, and not the tab itself. I know it will take a ControlTemplate to do it; I am trying to figure out what to put in the control template. Put another way, How do I specify that a particular brush should be applied to all inactive tabs? Thanks for your help.

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  • WPF Binding issues

    - by Nitin Chaudhari
    I have WPF window which binds a local Dependency property to a property of my usercontrol. So now I see the value which the window gave me in my usercontrol. I achieve this by setting DataContext of window to the window itself Now once the window is loaded i set the DataContext of usercontrol to a ViewModel class, and at some point of time(based on user action) the control changes values in the control. All fine so far. But now the changed value is not reflected in Windows dependency property. How I can resolve this issue?

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  • Binding a slider value on the height of its thumb in WPF

    - by sofri
    Hi, I have a databinding problem in WPF. I would like to "customise" a slider in a way that the thumb grows when you move the slider to the right and the thumb shrinks when you move the slider to the left. So I edited the template for the slider and changed the look of the slider so the slider looks like I want it to. But now I have to bind the height of the thumb to the value of the slider but I do not know how that works. I did some simple data binding things but I cannot figure out how I can bind this "thumb height" that's inside of my slider's template to the slider's value that's inside the User Control where my slider is in. So how can I do it?

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  • WPF binding and pointers

    - by Eran
    hey guys, I have a WPF application that contains windows with few user controls and Coordinator object. the window and all its user controls pointing to an object, which instace is in the Coordinator, by thier DataContext. the problem is that I want to change this object (e.g. create new object()) in the Coordinator but I want all the dataContexts to point to the new object. I tried to send the object by ref to the window constructor but it didn't help. any idea about how can I rewrite the memory location that all pointers are pointing to? (I don't want to repalce the properties in object since its a lot of work nor to use a middle object that points to the replaced object) Thanks Eran

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  • how to bind to the results of a query in WPF

    - by randyc
    I have a query that hits a service and returns the results back to me as an indexed collection static void QueryActivities() { QueryClient qc = new QueryClient("BasicHttpBinding_IQuery"); QueryFilter filter = new QueryFilter(); filter.CallForService = false; var result = qc.GetFilteredActivityIndex(filter); result.Clone(); //inserted this just to test return in debug mode } WHen this is executed I get a return of 5 records ( actually five rows of data with multiple values per each row. id, type, date, address etc). I would like to bind this return to a gridview within a WPF application. Is there a way to refernce and bind to result variable or do I need to create a new collection and then add the return of result to the new collection? thank you

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  • WPF - Make two controls the same size

    - by John Michaels
    Is there any way to make two controls that are in different containers the same size in WPF? For example, suppose you have two textboxes: textbox1 and textbox2. Textbox1 is in a grid and its size can grow and shrink when the user resizes the window. Textbox2 is in another part of the window and I need it to always have the same size as textbox1. Is there any way to do this? Keep in mind SharedSizeGroup will not work because the textboxes are in different containers. Also, I've tried binding textbox2's height property to textbox1 and that doesn't seem to work either. Finally, I tried catching textbox1's SizeChanged event, but its Height property is always NaN for some reason.

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  • WPF TreeView binding to a simple object

    - by esse
    I have a simple object as such: public class Info { public string Name {get; set;} public int Count {get; set;} public DateTime TimeStamp {get; set;} } I want to bind a collection of these objects to a WPF TreeView and have the properties on the Info objects show up as sub TreeViewItems, like so: Item 1 Name: Bill Count: 3 TimeStamp: 12/05/2010 09:06:00 AM Item 2 Name: Chris Count: 22 TimeStamp: 11/05/2010 11:34:00 AM Item 3 Name: Toby Count: 1 TimeStamp: 09/05/2010 05:55:00 PM How can I achieve this through XAML?

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  • WPF, animate over container boundaries

    - by ImIan
    Hi, I'm learning WPF and have a specific goal. Imagine you have a grid (3 rows by 3 columns), and a control, say a simple blue rectangle fills the middle cell. When I click on the cell I want the square to rotate smoothly through 180 degrees. The specific issue I have at the moment is; as the rectangle rotates, it won't change its dimensions, so it will extend beyond the boundary of the cell. I don't want it to clip, i want it to appear on top, partially obscuring surrounding cells. The second part of this is, if there is one cell that fills the entire window, and I click on the blue rectangle in that cell, can I make the rectangle rotate and extend beyond the sides of the form? If that doesn't make sense, please ask. I'm finding it hard to google because I don't know the exact terms I should be using. Thank you

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  • Wrapping WPF UserControl inside VisualStudio Item Template

    - by karthik84
    I am currently started working on a project which will allow users to design reports inside visual studio. Previously, for my similar Winforms App, I had extended the IComponent (Component Class) and wrote our VS Like designer kind of custom control which will allow users to drag drop controls from the visual studio toolbox and then I export it as a VisualStudio C#&VB ItemTemplate. Now I am trying to recreate the same control using WPF considering its power, extensiblity. Could anyone shed some lights on this, on what would be the most preferable way of doing this ? Thanks in advance.

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  • Splitting up/merging windows in WPF

    - by drasto
    I'm new to WPF but I need to implement following functionality: I have a window that contains one Grid (might be changed to stack panel or something else). In that Grid I have 2 columns, each of them contains another Grid. Lets call them gridFirst and gridSecond. There is also GridSplitter in first column allowing to resize the columns. I want to provide a button that will allow to separate gridFirst from this window and display it "as it is" in another window. How do I do that? It would be nice if the new window had a same menu as the original window without me having to copy-paste (that not a good coding practise) all its code to the new window. Thanks for answers

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