How to bind Close command to a button

Question

The easiest way is to implement ButtonClick event handler and invoke Window Close   method  but how doing this through a Command binding

User · Answer

One option that I ve found to work is to set this function up as a Behavior   The Behavior       public class WindowCloseBehavior   Behavior lt Window gt        public bool Close               get   return  bool  GetValue CloseTriggerProperty             set   SetValue CloseTriggerProperty  value                public static readonly DependencyProperty CloseTriggerProperty           DependencyProperty Register  Close   typeof bool   typeof WindowCloseBehavior               new PropertyMetadata false  OnCloseTriggerChanged         private static void OnCloseTriggerChanged DependencyObject d  DependencyPropertyChangedEventArgs e                var behavior   d as WindowCloseBehavior           if  behavior    null                        behavior OnCloseTriggerChanged                         private void OnCloseTriggerChanged                    when closetrigger is true  close the window         if  this Close                        this AssociatedObject Close                        On the XAML Window  you set up a reference to it and bind the Behavior s Close property to a Boolean  Close  property on your ViewModel   xmlns i  http   schemas microsoft com expression 2010 interactivity   lt i Interaction Behaviors gt       lt behavior WindowCloseBehavior Close   Binding Close     gt   lt  i Interaction Behaviors gt    So  from the View assign an ICommand to change the Close property on the ViewModel which is bound to the Behavior s Close property   When the PropertyChanged event is fired the Behavior fires the OnCloseTriggerChanged event and closes the AssociatedObject    which is the Window

User · Answer

All it takes is a bit of XAML      lt Window x Class  WCSamples Window1          xmlns  http   schemas microsoft com winfx 2006 xaml presentation          xmlns x  http   schemas microsoft com winfx 2006 xaml  gt       lt Window CommandBindings gt           lt CommandBinding Command  ApplicationCommands Close                          Executed  CloseCommandHandler   gt       lt  Window CommandBindings gt       lt StackPanel Name  MainStackPanel  gt           lt Button Command  ApplicationCommands Close                   Content  Close Window    gt       lt  StackPanel gt   lt  Window gt    And a bit of C      private void CloseCommandHandler object sender  ExecutedRoutedEventArgs e        this Close         adapted from this MSDN article

User · Answer

In the beginning I was also having a bit of trouble figuring out how this works so I wanted to post a better explanation of what is actually going on   According to my research the best way to handle things like this is using the Command Bindings  What happens is a  Message  is broadcast to everything in the program  So what you have to do is use the CommandBinding  What this essentially does is say  When you hear this Message do this     So in the Question the User is trying to Close the Window  The first thing we need to do is setup our Functions that will be called when the SystemCommand CloseWindowCommand is broadcast  Optionally you can assign a Function that determines if the Command should be executed  An example would be closing a Form and checking if the User has saved   MainWindow xaml cs  Or other Code-Behind   void CloseApp  object target  ExecutedRoutedEventArgs e              Code to check for State before Closing          this Close       void CloseAppCanExecute  object sender  CanExecuteRoutedEventArgs e              Logic to Determine if it is safe to Close the Window          e CanExecute   true      Now we need to setup the  Connection  between the SystemCommands CloseWindowCommand and the CloseApp and CloseAppCanExecute  MainWindow xaml  Or anything that implements CommandBindings    lt Window CommandBindings gt       lt CommandBinding Command  SystemCommands CloseWindowCommand                      Executed  CloseApp                      CanExecute  CloseAppCanExecute   gt   lt  Window CommandBindings gt    You can omit the CanExecute if you know that the Command should be able to always be executed Save might be a good example depending on the Application  Here is a Example    lt Window CommandBindings gt       lt CommandBinding Command  SystemCommands CloseWindowCommand                      Executed  CloseApp   gt   lt  Window CommandBindings gt    Finally you need to tell the UIElement to send out the CloseWindowCommand    lt Button Command  SystemCommands CloseWindowCommand  gt    Its actually a very simple thing to do  just setup the link between the Command and the actual Function to Execute then tell the Control to send out the Command to the rest of your program saying  Ok everyone run your Functions for the Command CloseWindowCommand     This is actually a very nice way of handing this because  you can reuse the Executed Function all over without having a wrapper like you would with say WinForms  using a ClickEvent and calling a function within the Event Function  like   protected override void OnClick EventArgs e            Function to Execute          In WPF you attach the Function to a Command and tell the UIElement to execute the Function attached to the Command instead   I hope this clears things up

User · Answer

Actually  it is possible without C  code  The key is to use interactions    lt Button Content  Close  gt     lt i Interaction Triggers gt       lt i EventTrigger EventName  Click  gt         lt ei CallMethodAction TargetObject   Binding ElementName window   MethodName  Close   gt       lt  i EventTrigger gt     lt  i Interaction Triggers gt   lt  Button gt    In order for this to work  just set the x Name of your window to  window   and add these two namespaces   xmlns i  http   schemas microsoft com expression 2010 interactivity   xmlns ei  http   schemas microsoft com expression 2010 interactions    This requires that you add the Expression Blend SDK DLL to your project  specifically Microsoft Expression Interactions    In case you don t have Blend  the SDK can be downloaded here

User · Answer

If the window was shown with Window ShowDialog    The simplest solution that I know of is to set the IsCancel property to true of the close Button   lt Button Content  quot Close quot  IsCancel  quot True quot    gt   No bindings needed  WPF will do that for you automatically  This properties provide an easy way of saying these are the  quot OK quot  and  quot Cancel quot  buttons on a dialog  It also binds the ESC key to the button  Reference  MSDN Button IsCancel property

User · Answer

I think that in real world scenarios a simple click handler is probably better than over-complicated command-based systems but you can do something like that   using RelayCommand from this article http   msdn microsoft com en-us magazine dd419663 aspx  public class MyCommands       public static readonly ICommand CloseCommand           new RelayCommand  o   gt    Window o  Close           lt Button Content  Close Window          Command   X Static local MyCommands CloseCommand           CommandParameter   Binding RelativeSource  RelativeSource FindAncestor                              AncestorType  x Type Window      gt

User · Answer

For  NET 4 5 SystemCommands class will do the trick   NET 4 0 users can use WPF Shell Extension google - Microsoft Windows Shell or Nicholas Solution         lt Window CommandBindings gt           lt CommandBinding Command   x Static SystemCommands CloseWindowCommand                            CanExecute  CloseWindow CanExec                           Executed  CloseWindow Exec    gt       lt  Window CommandBindings gt       lt  -- Binding Close Command to the button control -- gt       lt Button ToolTip  Close Window  Content  Close  Command   x Static SystemCommands CloseWindowCommand    gt    In the Code Behind you can implement the handlers like this       private void CloseWindow CanExec object sender  CanExecuteRoutedEventArgs e                e CanExecute   true             private void CloseWindow Exec object sender  ExecutedRoutedEventArgs e                SystemCommands CloseWindow this

[wpf] How to bind Close command to a button

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