Let TextBox stretch to fill width in StackPanel

Question

I have a StackPanel in my WinRT C# Metro app that I want to use as container for a label/value pair (TextBlock and TextBox) like this:

Answer 1

Unfortunately the alternative (DockPanel) isnt available for Metro. You could try a WrapGrid, but I dont know if it'll solve your problem (Ive never used it).

The only real way of doing this is using a Grid as you described: