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MouseEventHandler Delegate

Represents the method that will handle mouse related routed events that do not specifically involve mouse buttons or the mouse wheel; for example, UIElement.MouseMove.

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

'Declaration
Public Delegate Sub MouseEventHandler ( _
	sender As Object, _
	e As MouseEventArgs _
)
'Usage
Dim instance As New MouseEventHandler(AddressOf HandlerMethod)
In XAML, you can use delegates but you cannot define your own.

Parameters

sender
Type: System.Object

The object where the event handler is attached.

e
Type: System.Windows.Input.MouseEventArgs

The event data.

This delegate is used with the following attached events:

This delegate is used with the following routed events. These routed events forward the previously listed attached events to make them more accessible to the general element model in WPF.

The attached events and the base element routed events share their event data, and the bubbling and tunneling versions of the routed events also share event data. This can affect the handled characteristics of the event as it travels the event route. For details, see Input Overview.

Other than the RoutedEventArgs properties that are relevant for all routed events, the most interesting properties of MouseEventArgs that you might use in a MouseEventHandler implementation are several properties that expose the current button state, such as LeftButton and MouseDevice. MouseDevice is useful particularly because you can check Captured on it.

Note that events that specifically deal with mouse button events use a different delegate, MouseButtonEventHandler. The mouse button properties are available on MouseEventArgs in case there are input modes or interactions that involve the buttons even if you are handling a non-button event.

This example shows how to change the dimensions of an object when the mouse pointer moves on the screen.

The example includes an Extensible Application Markup Language (XAML) file that creates the user interface (UI) and a code-behind file that creates the event handler. For the complete sample, see Moving an Object with the Mouse Pointer Sample.

The following XAML creates the UI, which consists of an Ellipse inside of a StackPanel, and attaches the event handler for the MouseMove event.

<Window x:Class="WCSamples.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="mouseMoveWithPointer"
    Height="400"
    Width="500"
    >
  <Canvas MouseMove="MouseMoveHandler"
          Background="LemonChiffon">
    <Ellipse Name="ellipse" Fill="LightBlue" 
             Width="100" Height="100"/>
  </Canvas>
</Window>

The following code behind creates the MouseMove event handler. When the mouse pointer moves, the height and the width of the Ellipse are increased and decreased.

' raised when the mouse pointer moves. 
' Expands the dimensions of an Ellipse when the mouse moves. 
Private Sub OnMouseMoveHandler(ByVal sender As Object, ByVal e As MouseEventArgs)

    'Get the x and y coordinates of the mouse pointer. 
    Dim position As System.Windows.Point
    position = e.GetPosition(Me)
    Dim pX As Double
    pX = position.X
    Dim pY As Double
    pY = position.Y

    'Set the Height and Width of the Ellipse to the mouse coordinates.
    ellipse1.Height = pY
    ellipse1.Width = pX
End Sub

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0

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