MouseWheelEventArgs.Delta 屬性

定義

命名空間:

System.Windows.Input

組件:

PresentationCore.dll

會得到一個表示滑鼠滾輪變化幅度的值。

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

public int Delta { get; }

member this.Delta : int

Public ReadOnly Property Delta As Integer

屬性值

Int32

輪子變化的幅度。 當滾輪向上旋轉（遠離使用者）時，此值為正;若滾輪向下旋轉（朝向使用者），則為負值。

範例

以下範例若滑鼠滾輪TextBox為正，則向上移動Delta;若滑鼠滾輪TextBox為負，則移動Delta向下。 該 TextBox 連接於 Canvas。

// 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

備註

這個值的有效上限和下限可能來自裝置實作或其他提升事件的呼叫者，因此未被定義。

另請參閱

• MouseWheelDeltaForOneLine