Universal Code

Question

i have a programm to write. It's too long to explain, so ill go with an easy example:

there are 9 labels in the C# Form. What i need is a universal piece of code that will allow me to change text of a label depending on which label was clicked. f.e. clicked label number1 so the text of 9th label with "9".

if it is somewhere here, then sorry for not searching, but i don't even know how to name it properly :)