ContentElement.CaptureMouse Method ()

 

Attempts to force capture of the mouse to this element.

Namespace:   System.Windows
Assembly:  PresentationCore (in PresentationCore.dll)

Public Function CaptureMouse As Boolean

Return Value

Type: System.Boolean

true if the mouse is successfully captured; otherwise, false.

To be captured, an element must be enabled. Check whether IsEnabled is true before you call CaptureMouse.

If calling CaptureMouse returns true, then IsMouseCaptured is also true.

If calling CaptureMouse returns true, then the GotMouseCapture and IsMouseCapturedChanged events are raised, with RoutedEventArgs.Source in the event data reported as the element where the CaptureMouse method is called. If you force capture, you might interfere with existing captures—especially with captures that relate to drag-and-drop with the mouse.

To clear mouse capture from all elements, call Mouse.Capture with the element parameter provided as null.

The following example captures the mouse or releases capture, based on whether the mouse is already captured by the element. Note that this example casts the prospective capture target element to the IInputElement interface, and is thus initially calling the IInputElement.CaptureMouse method. Casting to IInputElement is a technique that is useful if you are unsure whether the element you want to have capture the mouse is a UIElement or a ContentElement. The interface cast and the interface method call then calls the appropriate type-specific CaptureMouse implementation internally without requiring a trial cast to either UIElement or ContentElement. This same casting technique works for other members that IInputElement defines, for instance many of the input-related events, and other input-related methods.

Private Sub CaptureMouseCommandExecuted(ByVal sender As Object, ByVal e As ExecutedRoutedEventArgs)
  MessageBox.Show("Mouse Command")
  Dim target As IInputElement = Mouse.DirectlyOver

  target = TryCast(target, Control)
  If target IsNot Nothing Then
	If Not target.IsMouseCaptured Then
	  Mouse.Capture(target)
	Else
	  Mouse.Capture(Nothing)
	End If
  End If
End Sub

.NET Framework
Available since 3.0
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