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MouseWheelEventHandler Delegate

Represents the method that will handle the UIElement.MouseWheel and ContentElement.MouseWheel routed events, as well as related attached and Preview events.

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

public delegate void MouseWheelEventHandler(
	Object sender,
	MouseWheelEventArgs e
)
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.MouseWheelEventArgs

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.

The Delta property is positive if the mouse wheel is moved forward (away from the user) or negative if the mouse wheel is moved downward (toward the user).

The following example moves a TextBox, which is attached to a Canvas, upward if the mouse wheel Delta is positive and moves the TextBox downward if the mouse wheel Delta is negative.

// Moves the TextBox named box when the mouse wheel is rotated. 
// The TextBox is on a Canvas named MainCanvas. 
private void MouseWheelHandler(object sender, MouseWheelEventArgs e)
{
    // If the mouse wheel delta is positive, move the box up. 
    if (e.Delta > 0)
    {
        if (Canvas.GetTop(box) >= 1)
        {
            Canvas.SetTop(box, Canvas.GetTop(box) - 1);
        }
    }

    // If the mouse wheel delta is negative, move the box down. 
    if (e.Delta < 0)
    {
        if ((Canvas.GetTop(box) + box.Height) <= (MainCanvas.Height))
        {
            Canvas.SetTop(box, Canvas.GetTop(box) + 1);
        }
    }

}

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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