MouseWheelEventArgs.Delta 屬性

定義

命名空間:

System.Windows.Input

組件:

PresentationCore.dll

取得值，這個值會指出滑鼠滾輪的變更量。

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

public int Delta { get; }

member this.Delta : int

Public ReadOnly Property Delta As Integer

屬性值

Int32

滾輪的變更量。 這個值在滑鼠滾輪向上旋轉 (遠離使用者) 時為正值，在滑鼠滾輪向下旋轉 (朝向使用者) 時則為負值。

範例

如果滑鼠滾輪是正數，則下列範例TextBox會向上移動，如果滑鼠滾輪DeltaDelta為負數，則會向下移動TextBox。 附加 TextBox 至 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

此值的有效上限和較低範圍可能來自引發事件的裝置實作或其他呼叫端，因此不會定義。

另請參閱

• MouseWheelDeltaForOneLine