How to get return value when BeginInvoke/Invoke is called in C#

Question

I\'ve this little method which is supposed to be thread safe. Everything works till i want it to have return value instead of void. How do i get the return value when BeginI

Answer 1

You have to Invoke() so you can wait for the function to return and obtain its return value. You'll also need another delegate type. This ought to work:

public static string readControlText(Control varControl) {
  if (varControl.InvokeRequired) {
    return (string)varControl.Invoke(
      new Func(() => readControlText(varControl))
    );
  }
  else {
    string varText = varControl.Text;
    return varText;
  }
}