In C# windows forms how a MaskedTextBox for email address can be implemented

Question

   public void Form1_Load(Object sender, EventArgs e) 
    {
          // Other initialization code
         mtxtEmailID.Mask = ".........."; 

what should be the Mask Type in place of dots

         mtxtEmailID.MaskInputRejected += new MaskInputRejectedEventHandler(mtxtEmailID_MaskInputRejected)
    }

   void mtxtEmailID_MaskInputRejected(object sender, MaskInputRejectedEventArgs e)
   {
      if(!Regex.IsMatch(txtEmailID.Text, "^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$"))  

the regex here gives me error, let me know what is the right one for email validation.

         {
         toolTip1.ToolTipTitle = "Invalid Input";
         toolTip1.Show("Enter valid email address", mtxtEMailID);
         }
   }

Answer 1

You can find info about MaskedTextBox here

---

If you want to validate an Email Address Regex is not the right choice.There are many corner cases that the regex wont cover...

Use MailAddress

try 
{
   address = new MailAddress(address).Address;
   //email address is valid since the above line has not thrown an exception
} 
catch(FormatException) 
{
   //address is invalid
}

---

But if you need regex, it should be:

.+@.+

Answer 2

This kind of approach in my project made the email validation simple considering only few factors which are important in email like '@' and '.' . I felt not to make it complex as email address for every one isn't compulsory.

    private void txtEmailID_Validating(object sender, System.ComponentModel.CancelEventArgs e)
    {
        string errorMsg;
        if (!ValidEmailAddress(txtEmailID.Text, out errorMsg))
        {
            // Cancel the event and select the text to be corrected by the user.
            e.Cancel = true;
            txtEmailID.Select(0, txtEmailID.Text.Length);

            // Set the ErrorProvider error with the text to display.  
            this.errorProvider1.SetError(txtEmailID, errorMsg);
        }
    }


    public bool ValidEmailAddress(string txtEmailID, out string errorMsg)
    {
        // Confirm that the e-mail address string is not empty. 
        if (txtEmailID.Length == 0)
        {
            errorMsg = "e-mail address is required.";
            return false;
        }

        // Confirm that there is an "@" and a "." in the e-mail address, and in the correct order.
        if (txtEmailID.IndexOf("@") > -1)
        {
            if (txtEmailID.IndexOf(".", txtEmailID.IndexOf("@")) > txtEmailID.IndexOf("@"))
            {
                errorMsg = "";
                return true;
            }
        }

        errorMsg = "e-mail address must be valid e-mail address format.\n" +
           "For example 'someone@example.com' ";
        return false;
    }

    private void txtEmailID_Validated(object sender, EventArgs e)
    {
        // If all conditions have been met, clear the ErrorProvider of errors.
        errorProvider1.SetError(txtEmailID, "");
    }