MouseWheelEventArgs.Delta 属性

定义

命名空间:

System.Windows.Input

程序集:

PresentationCore.dll

获取指示鼠标滚轮变更量的值。

public:
 property int Delta { int get(); };

public int Delta { get; }

member this.Delta : int

Public ReadOnly Property Delta As Integer

属性值

Int32

鼠标滚轮的变更量。 如果鼠标滚轮朝上旋转（背离用户的方向），则该值为正；如果鼠标滚轮朝下旋转（朝着用户的方向），则该值为负。

示例

以下示例TextBox在鼠标滚轮为正数时向上移动 ;如果鼠标滚轮DeltaDelta为负数，则向下移动 TextBox 。 附加到 TextBoxCanvas。

// 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);
        }
    }
}

' Moves the TextBox named box when the mouse wheel is rotated.
' The TextBox is on a Canvas named MainCanvas.
Private Sub MouseWheelHandler(ByVal sender As Object, ByVal e As MouseWheelEventArgs)
    ' If the mouse wheel delta is positive, move the box up.
    If e.Delta > 0 Then
        If Canvas.GetTop(box) >= 1 Then
            Canvas.SetTop(box, Canvas.GetTop(box) - 1)
        End If
    End If

    ' If the mouse wheel delta is negative, move the box down.
    If e.Delta < 0 Then
        If (Canvas.GetTop(box) + box.Height) <= MainCanvas.Height Then
            Canvas.SetTop(box, Canvas.GetTop(box) + 1)
        End If
    End If

End Sub

注解

此值的有效上限和下限范围可能来自引发事件的设备实现或其他调用方，因此未定义。

另请参阅

• MouseWheelDeltaForOneLine