TEXTBOX VALIDATION FOR INDIAN PAN CARD NUMBER USING TEXTBOX VALIDATINGEVENT

In this post we will the sample code for validating Textbox in windows c# for indian pan card number using Regular Expression in TextBox Validating Event . In the below code we are using a errorprovider to show if the entered pan number is in wrong / invalid format.

private void txt_PanNo_Validating(object sender, CancelEventArgs e)
        {
            System.Text.RegularExpressions.Regex rPan = 
                new System.Text.RegularExpressions.Regex(@"^([a-zA-Z]){5}([0-9]){4}([a-zA-Z]){1}?$");
            if (txt_PanNo.Text.Length > 0)
            {
                if (!rPan.IsMatch(txt_PanNo.Text))
                {
                    errorProvider2.SetError(txt_PanNo, "Invalid PAN Card Number");
                    txt_PanNo.SelectAll();
                    e.Cancel = true;
                }
                else
                {
                    errorProvider2.Clear();
                }
            }
            else
            {
                errorProvider2.Clear();
            }
        }