WPF TextBlock font resize to fill available space in a Grid

Question

I have some text that is displayed at run time in a textblock. I want the font size to be the biggest it can be to fill the area that is given. I think I have the textblock

Answer 1

The WPF ViewBox control can grow / shrink with its contents to the available space.

Just place your TextBlock within a ViewBox as;

ViewBox is typically scaled by its container.