Maskedtextbox shall accept every kind of numeral version

Question

I need a Maskedtextbox/Textbox which one does accept versions just like : Exaple: X.X.X.X or X.X.X.XX or X.XX.X.X and so on (X = a digit)

Is there a possibility that i can say no alphabetical/symbol-inputs, it must have 4 points, and it cant be null. (probably i need a Textbox insteat of a Manskedtextbox)

I set the mask of my Maskedtextbox under Properties --> Mask

Current Mask = 9.9.9.9 Currently my Maskedtextbox does accept only X.X.X.X

Please correct me :) I'm learning so every constructive criticism is welcome :)

Answer 1

You could do something like this or use RegEx I'm sure

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    bool handled = false;
    //test if digit
    if (char.IsDigit(e.KeyChar))
    {
        //only allow 2 digits
        //test if length is long enough to contain a prior char
        if (textBox1.Text.Length - 1 >= 0)
        {
            //test if prior char is digit
            if (char.IsDigit(textBox1.Text[textBox1.Text.Length -1]))
            {
                //test if length is long enough to have 2nd prior char
                if (textBox1.Text.Length -2 >= 0)
                {
                    //test 2 prior char if it's a digit because you
                    //only want to allow 2 not 3
                    if (char.IsDigit(textBox1.Text[textBox1.Text.Length - 2]))
                    {
                        handled = true;
                    }
                }
            }
        }
    }
    //test if decimal
    else if (e.KeyChar.Equals('.'))
    {
        //only allow 4 decimals
        if (textBox1.Text.Count(t => t.Equals('.')).Equals(3))
        {
            handled = true;
        }
        else
        {
            //don't allow multiple decimals next to each other
            //test if we have prior char
            if (textBox1.Text.Length - 1 >= 0)
            {
                //test if prior char is decimal
                if (textBox1.Text[textBox1.Text.Length - 1].Equals('.'))
                {
                    handled = true;
                }
            }
        }
    }
    else
    {
        handled = true;
    }
    e.Handled = handled;
}

Hooking up events from the designer ...