布局更改控件的布局

我有一个LayoutTransformControl，其中有一个包含图像和画布的Grid。在应用程序中的某个位置，单击按钮时，我正在Canvas中动态添加一些Thumb控件以实现拖放。问题是如果我为LayoutTransformControl设置了角度，则单击同一按钮时，我会假设它先绘制所有Thumb控件，然后在我首先创建Canvas和Thumbs时翻转Layout控件，但似乎正在更新整个布局和Thumb控件都超出了Canvas的位置。有没有一种方法可以先渲染所有我的Thumb，然后更改角度，以便将整个控件旋转到该角度。

如果角度为0，即如果我不应用变换，则Thumb控件在另一个下方出现，如下所示。

当我说角度为270时，这是我的问题，Thumb控件从画布移开。

xaml.cs

     private void BtnCapture_Click(object sender, RoutedEventArgs e)
    {
    BarCodeImage.Height = cnvBarCodeImage.Height = MainLayoutControl.Height=480;
    BarCodeImage.Width = cnvBarCodeImage.Width = MainLayoutControl.Width;

//This code will create the canvas.
                    for (int i = 0; i < 2; i++)
                    {
                        var item = Selected.WindowLocations[i];

                        var dimensionsItem = new Dimensions();

                        dimensions.Add(new Dimensions()
                        {
                            Height = 262,
                            Width = 142,
                            Left = 395,
                            Top = 44,
                            Text = string.Empty,
                        });

                        dimensions.Add(new Dimensions()
                        {
                            Height = 106,
                            Width = 147,
                            Left = 395,
                            Top = 342,
                            Text = string.Empty,
                    }
    CreateThumbs(2, dimensions); //This will create the Thumbs and add to the Canvas
     RotateImage(270);
    }

      private void RotateImage(int Angle)
            {
                MainLayoutControl.Transform = new RotateTransform()
                {
                    Angle = Angle
                };
            }

    private void CreateThumbs(int numberOfWindows, List<Dimensions> dimensions)
            {
                ClearOrRemoveAllChildren();
                Thumb th = null;
                for (int i = 0; i < numberOfWindows; i++)
                {
                    th = new Thumb();
                    th.Name = i.ToString();
                    var item = dimensions[i];
                    th.Width = item.Width;
                    th.Height = item.Height;
                    th.Foreground = new SolidColorBrush(Windows.UI.Colors.Transparent);
                    th.BorderBrush = item.BorderColor;
                    th.BorderThickness = new Thickness(3);
                    th.Template = GetThumbTemplate(item.Text);
                    th.DragDelta += (sender, e) => Th_DragDelta(sender, e, dimensions);
                    th.DragCompleted += (sender, e) => Th_DragCompleted(sender, e, item.IsImageRotated);
                    Canvas.SetLeft(th, item.Left);
                    Canvas.SetTop(th, item.Top);
                    cnvBarCodeImage.Children.Add(th);
                }
            }

这是我的xaml

<uwpControls:LayoutTransformControl x:Name="MainLayoutControl" Grid.Row="4" HorizontalAlignment="Center" VerticalAlignment="Center" Width="640">

                    <Grid x:Name="gridBarImagePanel">
                        <Image x:Name="BarCodeImage" 
                               RenderTransformOrigin="0.5,0.5"></Image>

                        <Canvas x:Name="cnvBarCodeImage" AllowDrop="True">

                        </Canvas>
                    </Grid>
                </uwpControls:LayoutTransformControl>