Adding visible elements to a custom Panel in Silverlight 3

Question

As I understand it, a Panel isn't meant to have any visible "chrome." The StackPanel, Grid and Canvas don't have any visible elements (with the exception of the gridlines, which they say are only for debugging layout.)

In my example, I am going to create a Custom Panel that uses Attached Properties to lay out its children controls. However, I want my Custom Panel to present a visible "grid" of sorts in the background. The look of the grid (sizing and positioning) will depend on the size and position of the child elements.

What are some of the ways to achieve this? Being very new to Silverlight and XAML in general, my first guess was to create a Custom Control which includes my custom panel for layout.

I think I'll be able to figure out the specific code, but I need to be pointed in the right direction in terms of what building blocks are appropriate for this scenario.

Answer 1

You are correct that custom Panels cannot show any extra chrome; they can only display their Children (Grid being an exception).

To do what you want to do, you could create a custom Panel which just adds extra Children to display the chrome. This would not be a good design though (since users of the Panel would see these extra items in the Children collection).

The best idea is to do what you said: create a custom Control that exposes a Children property. This control could internally use a private custom Panel to lay out these elements (e.g. TabControl uses a special TabPanel for laying out the tabs). In the Controls default template, you might want to use TemplateBinding on the Panels' Children property to your Control's Children property.