validation of C#

You can do the validation using regular expressions in C#. The Regex class provides the functionality for regular expression parsing. A code snippet for matching license plates like you wanted is below: string test = Console.ReadLine(); if (Regex.IsMatch(test, @"\b\d{3}-\b[a-zA-Z]{3}\b")) { Console.WriteLine("Licence plate!"); } else { Console.WriteLine("Duh!"); } This may not be a 100% correct as I did only very basic testing on it. I got this code with help from the following site which discusses regular expressions in some detail: http://www.devhood.com/tutorials/tutorial_details.aspx?tutorial_id=523 You can just do a google search on C# regular expressions to learn more.

another way is to use Regex (look it up in help)

thanks. there is another method you can use sub string

Here's something for ya: Wire the KeyPress event handler for the textbox, and in it, use Char.IsDigit() method or Char.IsLetter() method to check field level validation. Do a simple if, else if... you know know the routine. JJ