Hi,

I want to validate multiple Email ids separated with comma(,) with single TextBox as CC.

please help me.

Thanks

Pankaj

You can use logic like this to indicate the position of invalid emails. You didn't say VB/C# so I assumed C#:

private void button3_Click(object sender, EventArgs e)
    {
      string input = @"a@b.com, a@c.com, ffff23805789232(*@#(*@#&)(*, a@d.com, e@f.com";
      System.Net.Mail.MailAddress[] addrs = GetEmails(input);
      if (addrs.Length == 0)
      {
        //No emails were entered. Do something
      }
      else
      {
        List<int> invalidEmailPositions = new List<int>();
        for (int i1 = 0; i1 < addrs.Length; i1++)
        {
          if (addrs[i1] == null)
            invalidEmailPositions.Add(i1+1); //+1 since we count from 0
        }
        if (invalidEmailPositions.Count > 0)
        {
          string errorMessage = string.Format("Invalid addresses in positions: {0}",
            string.Join(", ", invalidEmailPositions.ConvertAll<string>(Convert.ToString).ToArray()));
          //They entered invalid emails in at least one position.
        }
        else
        {
          //You have all of the emails validated
        }
      }
      
    }

    private System.Net.Mail.MailAddress[] GetEmails(string s)
    {
      List<System.Net.Mail.MailAddress> lst = new List<System.Net.Mail.MailAddress>();
      if (string.IsNullOrEmpty(s))
        return lst.ToArray();
      
      string[] addrs = s.Split(new char[] { ',' }, StringSplitOptions.None);
      foreach (string email in addrs)
      {
        try
        {
          System.Net.Mail.MailAddress ma = new System.Net.Mail.MailAddress(email);
          lst.Add(ma);
        }
        catch (FormatException)
        {
          lst.Add(default(System.Net.Mail.MailAddress));
        }
      }
      return lst.ToArray();
    }