MouseWheelEventHandler Delegate
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MouseWheelEventHandler Delegate


Represents the method that will handle the UIElement.MouseWheel and ContentElement.MouseWheelrouted 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


Type: System.Object

The object where the event handler is attached.

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);


.NET Framework
Available since 3.0
Available since 3.0
Windows Phone Silverlight
Available since 7.0
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