Disable delete button on RichTextBox WF

Question

I am trying to disable people from deleting a textbox in a richtextbox. The project is using windows form.

Here is the code I have:

    private void         


        

Answer 1

You must add Back key to prevent delete :

private void richTextBox1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Back || e.KeyCode == Keys.Delete)
    {
        e.Handled = true;
        MessageBox.Show("Delete Pressed");
        // Does not show message box...
    }
}

Edit:

Non-selectable RichTextBox :

public class ViewOnlyRichTextBox : System.Windows.Forms.RichTextBox {
    // constants for the message sending
    const int WM_SETFOCUS = 0x0007;
    const int WM_KILLFOCUS = 0x0008;

    protected override void WndProc(ref Message m) {
        if(m.Msg == WM_SETFOCUS) m.Msg = WM_KILLFOCUS;

        base.WndProc (ref m);
    }
}