单击另一个按钮时更改按钮的背景

I am currently experimenting in WPF and just created a UniformGrid with 800 buttons which are created in a for loop. All buttons have their own names and share the same click event. What I want to do now is the following: I want to click the first button (rect0) to change the color of this button and the next one (rect1). I am totally stuck right now because everything I write into the click event refers to the button I clicked.I am currently experimenting in WPF and just cr