Will event stop another function?

I wanted to make event on my label, so when someone puts the mouse over that label he will get new messagebox saying "You just crossed your mouse over the label".

But, my problem would be if that event stops already running function?

For example.. let's say i have function:

______________________________________

private void func()

{

// some kind of code that loops

}

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And so that function has looping code inside of it, and it's running at the moment. And if i cross the label with my mouse pointer, will that event cause  "func" function to stop?

If that's true, how can i make it not to stop already running function?

If that's not true, is it possible to stop a function by raising that event?