I have a Window with my user control and I would like to make usercontrol width equals window width. How to do that?
The user control is a horizontal menu and contains a
You need to make sure your usercontrol hasn't set it's width in the usercontrol's xaml file. Just delete the Width="..." from it and you're good to go!
EDIT: This is the code I tested it with:
SOUserAnswerTest.xaml:
a b c
Window1.xaml: