Unable to position Rectangle in Canvas in Silverlight 4 - silverlight

Question

I'm new to SL. I just wrote a simple app drawing a Rectangle and Line. When I try to position the Rectangle it has no effect and always puts it in the lower-right corner:
Canvas.SetLeft(r, 100);
Canvas.SetTop(r, 100);
When I try to use SetValue, the app hangs (ie. get stuck on the loading animation in the browser):
r.SetValue(Canvas.LeftProperty, 10);
r.SetValue(Canvas.TopProperty, 10);
Has anyone experienced anything like this, and/or know how to get past it?
[EDIT] Here's the more complete source:
public MainPage()
{
InitializeComponent();
Rectangle r = new Rectangle() {
Stroke = new SolidColorBrush(Colors.Black),
Width = 100,
Height = 20,
Fill = new SolidColorBrush { Color = Color.FromArgb(80, 143, 12, 28) }
};
//r.SetValue(Canvas.LeftProperty, 10);
//r.SetValue(Canvas.TopProperty, 10);
Canvas.SetLeft(r, 100);
Canvas.SetTop(r, 100);
this.LayoutRoot.Children.Add(r);
var line = new Line() {
Stroke = new SolidColorBrush(Colors.Black),
X1 = 10, Y1 = 10, X2 = 100, Y2 = 200
};
LayoutRoot.Children.Add(line);
}
I've tried putting the LayoutRoot..Add call before the SetValue/SetLeft but it doesn't seem to make any difference.

Answer 1

Try this :
this.LayoutRoot.Children.Add(r);
Canvas.SetLeft(r, 100);
Canvas.SetTop(r, 100);
Rather than:
Canvas.SetLeft(r, 100);
Canvas.SetTop(r, 100);
this.LayoutRoot.Children.Add(r);
Update : It got fixed since in XAML it is by default a grid tag as LayoutRoot. After changing it to a canvas tag and it no longer gets stuck.