拖动时更改 ZIndex

Question

I'm dragging around different StackPanel s inside a canvas but when I drag over another StackPanel inside the same canvas, that is overlapping it grabs that one instead of the one I'm currently dragging. I am trying to solve this with Zindex . Is this the correct way? My code so far:

private void UIElement_OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    StackPanel sp = (StackPanel)sender;
    Panel.SetZIndex(sp, 99999);
    sp.Background = Brushes.Red;
    Console.WriteLine(Panel.GetZIndex(sp));
}

private void UIElement_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    StackPanel sp = (StackPanel)sender;
    Panel.SetZIndex(sp, -10);
    sp.Background = Brushes.Green;
    Console.WriteLine(Panel.GetZIndex(sp));
}

private void UIElement_OnMouseMove(object sender, MouseEventArgs e) 
{
    if (e.LeftButton == MouseButtonState.Pressed) 
    { 
        StackPanel sp = (StackPanel) sender; 
        SymbolModel sm = sp.DataContext as SymbolModel; 
        Point pos = e.GetPosition(SymbolViewControl); 
        if (pos.X > 10 && pos.Y > 10) 
        { 
            sm.CanvasTop = pos.Y-10; 
            sm.CanvasLeft = pos.X-10; 
        } 
    } 
}

The colors and the writeline are only for testing and they seem to work as intended. The Zindex gets set correctly on button down and button up but the elements seem to not care.

Answer 1

Using CaptureMouse and ReleaseMouseCapture inside the mousedown and mouseup methods seems to have fixed the main issue.

private void UIElement_OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        StackPanel sp = (StackPanel)sender;
        Panel.SetZIndex(sp, 99999);
        sp.CaptureMouse(); //This
    }

    private void UIElement_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        StackPanel sp = (StackPanel)sender;
        Panel.SetZIndex(sp, -10);
        sp.ReleaseMouseCapture(); //And this
    } 

It new holds onto the one i started grapping no matter what unltil release. The Z-index is still wrong and i still need a fix for that.