Problem sending mail to mlutiple users in C#

Question

Hi,

I'm trying to develop a wpf application for sending bulk email using Microsoft outlook app. I'm using a datagridview from which to, cc, and attachment will be extracted. Besides, for each mail, there'll be multiple to(s) and cc(s). If to and/or cc field contain single mail address, it works. But when multiple to or cc added, it gets the following error.

System.Runtime.InteropServices.COMException: 'Outlook does not recognize one or more names. '

I things it's issue with mail separation and put some efforts to resolve it.

Here's my datagridview data

Here's the code for sending mail.

   private void BtnSendMail_Click(object sender, RoutedEventArgs e)
    {

        foreach (DataRowView rows in dgdData.ItemsSource)
        {

            try
            {
                Outlook.Application oApp = new Outlook.Application();
                Outlook.MailItem oMsg = (Outlook.MailItem)oApp.CreateItem(Outlook.OlItemType.olMailItem);
                Outlook.Recipients oRecips = oMsg.Recipients;

                List<string> sTORecipsList = new List<string>();
                List<string> sCCRecipsList = new List<string>();


                var to = rows.Row.ItemArray[1].ToString();            
                var cc = rows.Row.ItemArray[2].ToString();
                var attachment = rows.Row.ItemArray[3].ToString();
                //var status = rows.Row.ItemArray[0] ="Sending";

                if (to.Contains(",") || to.Contains(";") || to.Contains(" "))
                {
                    string[] tos = Regex.Split(to, ",; ");
                    // string[] lines = Regex.Split(value, "\r\n");
                    for (int i = 0; i < tos.Length; i++)
                    {
                        //mail.To.Add(new MailAddress(tos[i]));

                        sTORecipsList.Add(tos[i]);

                    }
                }
                else
                {
                    sTORecipsList.Add(to);

                }

                if (cc.Contains(",") || cc.Contains(";") || cc.Contains(" "))
                {
                    string[] ccs = Regex.Split(cc, ",; ");
                    // string[] lines = Regex.Split(value, "\r\n");
                    for (int i = 0; i < ccs.Length; i++)
                    {
                        //mail.To.Add(new MailAddress(tos[i]));

                        sCCRecipsList.Add(ccs[i]);

                    }
                }
                else
                {
                    sCCRecipsList.Add(cc);

                }



                oMsg.Body = "Sample Text";///rtbBody.Text.ToString();


                string sDisplayName = "MyAttachment";
                int iPosition = oMsg.Body.Length + 1;
                int iAttachType = (int)Outlook.OlAttachmentType.olByValue;
                Outlook.Attachment oAttach = oMsg.Attachments.Add(attachment, iAttachType, iPosition, sDisplayName);

                oMsg.Subject = txtSubject.Text.ToString();

                foreach (string t in sTORecipsList)
                {
                    Outlook.Recipient recipTo = oMsg.Recipients.Add(t);
                    recipTo.Type = (int)Outlook.OlMailRecipientType.olTo;
                }

                foreach (string c in sCCRecipsList)
                {
                    Outlook.Recipient recipCc = oMsg.Recipients.Add(c);
                    recipCc.Type = (int)Outlook.OlMailRecipientType.olCC;
                }


                oMsg.Recipients.ResolveAll();

                Thread.Sleep(2000);

                oMsg.Send();
                rows.Row.ItemArray[0] = "Sent";

                sTORecipsList = null;
                sCCRecipsList = null;
                //recipTo = null;
                oRecips = null;
                oAttach = null;
                oMsg = null;
                oApp = null;


                Thread.Sleep(2000);



            }

            catch (Exception)
            {
                throw;
            }



        }

        MessageBox.Show("All message sent!!");
    }

Waiting for experts help. Thanks in advance.

Regards, Subrata

Answer 1

The second argument to Regex.Split should be a regex pattern. So to match , or ; as a delimiter, you'd use a pattern like \s*[,;]\s* (the \s* allows optional whitespace around the delimiters):

string[] tos = Regex.Split(to, @"\s*[,;]\s*");

Note this uses the @ symbol on the string to preserve the escapes.