在表单加载时调用 KeyDown 事件

Question

I would want to launch a KeyDown Event on Form_Load however its taking me somewhere else in the Form_Load event.

Form_Load:

int static_int = 0;
private void Form1_Load(object sender, EventArgs e)
{
    if(condition == true)
    {
        txtInput.Text = "something";
        txtInput.Focus();
        SendKeys.Send("{Enter}");
        int somegeneratednubmer = 20;
        static_int = static_int + somegeneratednumber;
        //somemore code here
    }

}

KeyDown:

private void txtInput_KeyDown(object sender, KeyEventArgs e)
{
  if(e.KeyCode == Keys.Enter)
  {
      static_int = 10;
      //somemore codes here too
  }

I would like to get the SUM of static_int and somegeneratednumber which is 30. However, after Debugging, I'm getting its initialized value of 0. From what I understood, after SendKeys.Send("{Enter}") the KeyDown event should proceed.

Why is it not??
How would I get the correct result? I really should do the KeyDown event on Form_Load , a conditional event...
or What am I doing wrong here?
Note: originally static_int is initialized on a Class

Answer 1

No, the KeyDown even will proceed at the earliest possible moment, which is when the appropriate message is executed from the form's message queue. That cannot happen before the Load event finishes, because that also on the message queue. Even if that weren't the case, SendKeys doesn't wait for the action to be processed. It just sends the message and returns immediately.

Another problem is that SendKeys sends the virtual keys to the currently active window. That can never be your window, since your window isn't even shown yet! When something behaves weird, a good first step is to read the documentation.

So, why is the value of static_int zero, instead of 20 or 30 ? Well, the likeliest case is an unhandled exception, and I'm pretty sure that's exactly what happens when you do tbxInput.Focus . The control doesn't quite exist yet, and it can't be made the input focus. If you have trouble understanding all this, you might want to find some book on the basics of how Windows windows work - there's nothing .NET can do about it, and it's places like this where the (very pretty) .NET abstraction leaks a lot. If you're planning to do any Windows UI development, you really need to know at least the basics.

However, that's completely unnecessary anyway. You don't have to execute a KeyDown event. Just make a method that's called from both the Load event handler and the KeyDown event handler.

Answer 2

try adding this event instead Form1 isn't loaded yet so no events yet.

private void Form1_Shown(Object sender, EventArgs e) 
{
   SendKeys.Send("{Enter}");
}

But truly this design is wrong