Only allowing up to three digit numeric characters in a text box

Question

Is there a way to only allow a user to input a maximum number of characters into a text box? I want the user to input a mark/grade and only be able to input 0 - 100. Below I

Answer 1

I think it is as simple as:

textBox1.MaxLength = 3;

Then you handle the maximum value on the Leave event:

    private void textBox1_Leave(object sender, EventArgs e)
    {
        string s = (sender as TextBox).Text;
        int i = Convert.ToInt16(s);

        if (i > 100)
        {
            MessageBox.Show("Number greater than 100");
            (sender as TextBox).Focus();
        }
    }

or

You could also use System.Windows.Forms.NumericUpDown where you can easily setup minimum and maximum.