Are event arguments passed by reference or value in C#?

Question

A rather simple question (I think), but I don\'t seem to see an answer already. I know that some values are passed via value (like int and long), and others are passed by refer

Answer 1

In the standard event pattern there are two references passed in:

 void FormClosing(object sender, FormClosingEventArgs e) { ... }

those two references are passed 'by value', using for example sender = null will have no effect outside the handling method.

But you can easily pass a value back:

void FormClosing(object sender, FormClosingEventArgs e)
{
    ...
    e.Cancel = true;  // this will pass back to the caller
}