public delegate int AsyncEventHandler(int a, int b);
public delegate void Del();
public Form2()
{
InitializeComponent();
Console.WriteLine("Start");
AsyncEventHandler asyncHandler = new AsyncEventHandler(Cal);
asyncHandler.BeginInvoke(1, 2, new AsyncCallback(Callback), null);
Console.WriteLine("End");
}
public int Cal(int a, int b)
{
int c = a + b;
Console.WriteLine(c);
return c;
}
public void Callback(IAsyncResult result)
{
AsyncEventHandler asyncHandler = (AsyncEventHandler)((AsyncResult)result).AsyncDelegate;
Console.WriteLine(asyncHandler.EndInvoke(result));
Console.WriteLine("CallBack End");
}