how to make a multiline textbox not accept Enter and Backspace

I have a multiline textbox which shouldn't accept alphabets, numbers, newline(enter key) and backspace. In short, the textbox.Text shouldn't be editable. But I do want the textbox to accept two shortcut keys - control and control+R. One way I can make the textbox un-editable is by making it read-only. But then the textbox wont accept any keystroke at all. In short, my shortcuts ( control and control+R) wont work( Control + R) with read-only method.

Can anyone help in this regard. That's all I have to do.

One thing I could do here is not to make the textbox read-only and then restrict the characters(alphabets and digits) that could be inputted in the textbox. With this code:

    private void txtResult_KeyPress(object sender, KeyPressEventArgs e)
    {
        // only modifier keys, escape, enter, backspace etc is accepted now
        e.Handled = !char.IsControl(e.KeyChar);
    }

    private void txtResult_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.Control == true)
        {
            if (e.KeyCode == Keys.R)
            {
                // do something
            }
            else
            {
                //do something
            }
        }

        if (e.KeyCode == Keys.Escape)
        {
            //do something
        }
    }

With this technique I can get the shortcuts(control and control+R) working. But the trouble with this method is that Enter and Backspace keys work as well making it possible to edit the text of textbox. How can I specifically restrict Enter and Backspace key being registered from the textbox, but开发者_如何转开发 let Control and Escape??

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did you try SuppressKeyPress = true ?

private void textBox2_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Control == true)
            {
                if (e.KeyCode == Keys.R)
                {
                    // do something
                }
                else
                {
                    //do something
                }
            }
            else
                e.SuppressKeyPress = true;


        }

---

Since you are handling the keys in the KeyDown event handler, why not have your KeyPress handler return that all keystrokes are handled?

So just set e.Handled = true no matter what. I believe the backspace and enter would be interpreted as control characters, also.

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The Enter and Backspace keys won't work if the textbox is set to ReadOnly, as you suggested early on in the question that you had done. Make sure the property is still set to true. You can either set it in the Properties window, or through code like so:

myTextBox.ReadOnly = true;

Then, you need to handle the KeyDown event for the textbox control, and watch for the specific keys that you're interested in. Something like this:

private void myTextBox_KeyDown(object sender, KeyEventArgs e)
{
   if (e.Control)
   {
      if (e.KeyCode == Keys.R)
      {
         MessageBox.Show("Pressed Ctrl+R");
      }
      else
      {
         MessageBox.Show("Pressed Ctrl");
      }
   }
   else if (e.KeyCode == Keys.Escape)
   {
      MessageBox.Show("Pressed Esc");
   }
}

This works exactly as expected, as long as the textbox is set to read-only. No other keys are recognized, and the user cannot change or modify any of the text in the textbox. You don't need to suppress the keypresses, as the control is already doing that when you set it to read-only. You also don't need to handle both the KeyDown and KeyPress events. KeyPress won't work for you anyway, as it doesn't let you handle control characters.