In ASP.NET, it's possible to get a reference to a control by Id at runtime using the FindControl method - something like this:

Label lblCustomerName = (Label) item.FindControl("lblCustomerName");

This can be helpful in dynamic code which might need to iterate through a large collection of elements in XAML.

In Silverlight, there is no FindControl method, but we can still get a reference to an object by name using the FindName method of a container:

TextBlock lblCustomerName = cnvContainer.FindName("lblCustomerName") as TextBlock

We can also access the Children collection of a container and query using a lambda expression:

TextBlock lblCustomerName = (cnvContainer.Children.First<UIElement>(label => label.GetValue(Canvas.NameProperty).ToString() == "lblCustomerName")) as TextBlock;

In the above example, we are getting a reference to an object named lblCustomerName inside a canvas named cnvContainer. We do so by using a lambda expression on the Children property, along with the Canvas.NameProperty which gives the variable (x:Name) property of a UIElement.