c# - 旋转后更改 WPF 元素的父元素(设置新坐标问题)

Question

我需要更改元素的父元素。 (用于组合/取消组合形状) 但是如果元素有旋转，我就不能为它设置新的位置。

我看到了this , this , this和 this页面和许多其他方式，但没有一个能正常工作。

请参阅my sample project和下图:

Rect1 的父级是ChildCanvas1，Rect2 的父级是ChildCanvas2，我想移动Rect1 和 Rect2 到 MainCanvas。 (并删除 ChildCanvas 和 ChildCanvas2)

我对 Rect1 这样做没有任何问题，因为它没有任何旋转。 但是 Rect2 有一个旋转(-20 度)，我无法为它正确设置新坐标。

请看这张图:

如何在旋转后更改元素的父级并正确设置新坐标？

更新:

请注意，我需要一种通用方法(对于大型应用程序中的分组/取消分组元素，每个元素(可能)都有 TranslateTransform 和 SkewTransform 和 RotateTransform 和 ScaleTransform)

XAML:

<Canvas x:Name="MainCanvas">
    <Canvas x:Name="ChildCanvas1" Width="500" Height="250" Background="Bisque" Canvas.Top="54">
        <Rectangle x:Name="Rect1" Width="200" Height="100" Fill="Red" Canvas.Left="150" Canvas.Top="100"/>
    </Canvas>

    <Canvas Name="ChildCanvas2" Width="500" Height="250" Background="Bisque" Canvas.Left="516" Canvas.Top="54">
        <Rectangle Name="Rect2" Width="200" Height="100" Fill="Red" Canvas.Left="150" Canvas.Top="100">
              <Rectangle.RenderTransform>
                <TransformGroup>
                    <SkewTransform AngleX="-40"/>
                <RotateTransform Angle="-20"/>
                </TransformGroup>
            </Rectangle.RenderTransform>
        </Rectangle>
    </Canvas>
    <Button Name="btn1" Click="btn1_Click" Content="Move Rect1 to MainCanvas and Remove ChildCanvas1" Width="356" Height="30" Canvas.Left="59" Canvas.Top="310"/>
    <Button Name="btn2"  Click="btn2_Click" Content="Move Rect2 to MainCanvas and Remove ChildCanvas2" Width="350" Height="30" Canvas.Left="590" Canvas.Top="310"/>

C# 代码:

GeneralTransform transform = Rect2.TransformToVisual(MainCanvas);
Rect rect = transform.TransformBounds(new Rect(0, 0, Rect2.Width, Rect2.Height));
double ChildCanvas2Left = Canvas.GetLeft(ChildCanvas2);
double ChildCanvas2Top = Canvas.GetLeft(ChildCanvas2);
ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Add(Rect2);
Canvas.SetLeft(Rect2, rect.Left);
Canvas.SetTop(Rect2, rect.Top);
MainCanvas.Children.Remove(ChildCanvas2);

Answer 1

将Rect2移动到MainCanvas后，需要重新计算Rect2。像这样:

Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));

完整代码:

private void btn2_Click(object sender, RoutedEventArgs e)
{       
    GeneralTransform transform = Rect2.TransformToVisual(MainCanvas);
    Rect rect = transform.TransformBounds(new Rect(0, 0, Rect2.Width, Rect2.Height));
    ChildCanvas2.Children.Remove(Rect2);
    MainCanvas.Children.Remove(ChildCanvas2);
    Canvas.SetLeft(Rect2, rect.Left);
    Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
    MainCanvas.Children.Add(Rect2);      
}

但是 Rect2.TransformToVisual 和 transform.TransformBounds 在您的情况下不是必需的，没有它们您可以做得更干净、更容易，并获得相同的结果。像这样:

ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Remove(ChildCanvas2);
Canvas.SetLeft(Rect2, Canvas.GetLeft(Rect2) + Canvas.GetLeft(ChildCanvas2));
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
MainCanvas.Children.Add(Rect2); 

编辑:一般方式:

ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Remove(ChildCanvas2);
Canvas.SetLeft(Rect2, Canvas.GetLeft(Rect2) + Canvas.GetLeft(ChildCanvas2));
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
Canvas.SetRight(Rect2, Canvas.GetRight(Rect2) + Canvas.GetRight(ChildCanvas2));
Canvas.SetBottom(Rect2, Canvas.GetBottom(Rect2) + Canvas.GetBottom(ChildCanvas2));
MainCanvas.Children.Add(Rect2);