maskedtextbox text rejected

Question

I am trying to figure out how to make it so that if I press my button to do a action, (like show a messagebox) and my maskedtextbox's text isn't a number, then it goes and does something like say that you can only have a number in the TextBox or something like that. I can't seem to figure it out.

I have tried to use this:

if (!System.Text.RegularExpressions.Regex.IsMatch(binTxtbx.Text, @"0-9"))
            e.Handled = true;

But if I use that it wont put any text into the maskedtextbox.

If you know if anyone asked the same question that I did, please tell me.

If you're using a MaskedTextBox the Mask property can (should) be used to prevent invalid entry MaskedTextBox.Mask = "000" — jac
I just don't like to have to have underscores in my MaskedTexBox. — Dozer789
That's fine, but it is still better to prevent the user from entering invalid data than it is to let them, then tell them afterward they can't do that. You could change the default _ prompt to a space character. I don't like that personally because it is non-standard, or you could use a TextBox and handle the KeyDown event to prevent non-numeric entry - stackoverflow.com/questions/463299/… — jac

sǝɯɐſ sǝɯɐſ · Accepted Answer · 2013-01-22T21:05:52

If you don't mind using a maskedTextBox, and just don't like the underscores (as you mentioned in your comment), simply change the PromptChar to a blank.

You can do this either in the Design View in the MaskedTextBox Properties, or in the code like this:

myMaskedTextBox.PromptChar = ' ';

Alternatively, (if you don't want to use a maskedTextBox) you could wire the KeyDown event to an EventHandler like this:

    private void numericComboBox_KeyDown(object sender, KeyEventArgs e)
    {
        try
        {
            e.SuppressKeyPress = false;

            // Determine whether the keystroke is a number from the top of the keyboard.
            if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
            {
                // Determine whether the keystroke is a number from the keypad.
                if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
                {
                    // Determine whether the keystroke is a backspace or arrow key
                    if ((e.KeyCode != Keys.Back) && (e.KeyCode != Keys.Up) && (e.KeyCode != Keys.Right) && (e.KeyCode != Keys.Down) && (e.KeyCode != Keys.Left))
                    {
                        // A non-numerical keystroke was pressed.
                        // Set the flag to true and evaluate in KeyPress event.
                        e.SuppressKeyPress = true;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            //Handle any exception here...
        }
    }

maskedtextbox text rejected

3 Answers