ContentElement.MouseEnter Event (System.Windows)

Public Event MouseEnter As MouseEventHandler

public event MouseEventHandler MouseEnter

public:
virtual  event MouseEventHandler^ MouseEnter {
	void add (MouseEventHandler^ value);
	void remove (MouseEventHandler^ value);
}

abstract MouseEnter : IEvent<MouseEventHandler,
    MouseEventArgs>
override MouseEnter : IEvent<MouseEventHandler,
    MouseEventArgs>

<object MouseEnter="MouseEventHandler" .../>

Implements

• Override OnMouseEnter to implement class handling for this event in derived classes.

MouseEnter is a Routed Events Overview that uses the direct event handling routing strategy. Direct routed events are not raised along a route; instead, they are handled in the same element where they are raised. However, they do enable other aspects of routed event behavior, such as event triggers in styles.

Although MouseEnter tracks when the mouse pointer enters the bounds of an element, this event more literally reports that the IsMouseOver property value has changed from false to true on this element.

This event creates an alias for the Mouse.MouseEnter attached event for this class, so that MouseEnter is part of the class members list when ContentElement is inherited as a base element. Event handlers that are attached to the MouseEnter event are attached to the underlying Mouse.MouseEnter attached event and receive the same event data instance.

This example shows how to change the color of an element as the mouse pointer enters and leaves the area occupied by the element.

This example consists of a Extensible Application Markup Language (XAML) file and a code-behind file.

Note
This example demonstrates how to use events, but the recommended way to achieve this same effect is to use a Trigger in a style. For more information, see Styling and Templating.

The following XAML creates the user interface, which consists of Border around a TextBlock, and attaches the MouseEnter and MouseLeave event handlers to the Border.

<StackPanel>
  <Border MouseEnter="OnMouseEnterHandler"
          MouseLeave="OnMouseLeaveHandler"
          Name="border1" Margin="10"
          BorderThickness="1"
          BorderBrush="Black"
          VerticalAlignment="Center"
          Width="300" Height="100">
    <Label Margin="10" FontSize="14"
           HorizontalAlignment="Center">Move Cursor Over Me</Label>
  </Border>
</StackPanel>

The following code behind creates the MouseEnter and MouseLeave event handlers. When the mouse pointer enters the Border, the background of the Border is changed to red. When the mouse pointer leaves the Border, the background of the Border is changed back to white.

Partial Public Class Window1
    Inherits Window

    Public Sub New()
        InitializeComponent()
    End Sub
    ' raised when mouse cursor enters the are occupied by the element
    Private Sub OnMouseEnterHandler(ByVal sender As Object, ByVal e As MouseEventArgs)
        border1.Background = Brushes.Red
    End Sub
    ' raised when mouse cursor leaves the are occupied by the element
    Private Sub OnMouseLeaveHandler(ByVal sender As Object, ByVal e As MouseEventArgs)
        border1.Background = Brushes.White
    End Sub
End Class

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
    }

    // raised when mouse cursor enters the area occupied by the element
    void OnMouseEnterHandler(object sender, MouseEventArgs e)
    {
        border1.Background = Brushes.Red;
    }

    // raised when mouse cursor leaves the area occupied by the element
    void OnMouseLeaveHandler(object sender, MouseEventArgs e)
    {
        border1.Background = Brushes.White;
    }
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Other Resources