Question

How can i stop keydown event in my current situation?

private void button1_Click(object sender, EventArgs e)
{
    textBox1.Focus();
    textBox1.KeyDown += new KeyEventHandler(MyKeyPress);
}

public void MyKeyPress(object sender, KeyEventArgs e)
{
    e.SuppressKeyPress = true;
    string first = e.Modifiers.ToString();

    if (first != "None")
    {
        if ((e.KeyCode != Keys.ShiftKey) && (e.KeyCode != Keys.Alt) && (e.KeyCode != Keys.ControlKey))
        {
            textBox1.Text = e.Modifiers.ToString() + " & " + e.KeyCode.ToString();
        }
    }
    else
    {
        textBox1.Text = e.KeyCode.ToString();
    }
    e.Handled = true;
}

As you can see – the event is triggered when user clicks on a button.. but how can I stop the it after the first output?

e.Handled = true;

does not help at all

Answer 1

If I get you right and you want to handle KeyPress event only once after clicking button, then you need unregister this handler in your MyKeyPress. Like this:

public void MyKeyPress(object sender, KeyEventArgs e)
{
  textBox1.KeyDown -= new KeyEventHandler(MyKeyPress);
  ...
}