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.

Answer 1

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 = ' ';

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EDIT:

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...
        }
    }