validation in windows application

u can use control validating event with errorprovider
example
here i have given an example to validate a textbox which accepts only integer the validate message is displayed on error provider
her is the code

private void textBox1_Validating(object sender, CancelEventArgs e)
        {
            try
            {
                int a = int.Parse(textBox1.Text);
            }
            catch
            {
                errorProvider1.SetError(textBox1, "Enter numbers only");
            }
        }

so here i have written the code in textBox1_Validating event

Hope this may help u

You can simply create methods and call accordingly to validate controls in Windows applications.as in mobile number validation

class Validations
    {
        public static bool phone(string no)
        {


            string pattern = @"^\d{10}$";
            //string data = "111111111111";
            if (Regex.IsMatch(no, pattern))
            {
                return false;
            }
            else
            {
                return true;
            }

        }
}

and on Leave event of text box you can call this method.

Various Regular Expressions are used for validations.

Using Regular Expressions..
Regex is the best method for valudation..