Question

I am sending emails from my application using the mailto:

 Process.Start("mailto:" + emailAddress + "?subject=" + subject + "&body=" 
                        + body);

When I use this with a small number of email addresses (10-20) it works fine, but I am testing it with a larger number (100+) but some of the emails are not being added to the recipient list.

Is there a limit to the number of emails I can add in this way? and there is, whats the limit?

Answer 1

If there is a limit, it depends on the underlying email client that is registered for mailto: links.

Sending emails this way starts a new Windows process to open an email sending window, typically Microsoft Outlook. It could well be there is a limit to the number of recipients that Outlook will permit or the size of the mailto: string.

A possible workaround could be to create two or more email messages instead, each with 20 or less email addresses.

Alternatively, you may want to explore the System.Mail.SmtpClient class and consider sending mail directly from your application. Reference here: http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.aspx