.Net System.Mail.Message adding multiple "To" addresses

Question

This question is pointless, except as an exercise in red herrings. The issue turned out to be a combination of my idiocy (NO ONE was being emailed as the host was not being specified and was incorrect in `web.config`) and the users telling me that they sometimes got the emails and sometimes didn't, when in reality they were NEVER getting the emails.** So, instead of taking proper steps to reproduce the problem in a controlled setting, I relied on user information and the "it works on my machine" mentality. Good reminder to myself and anyone else out there who is sometimes an idiot. I just hit something I think is inconsistent, and wanted to see if I'm doing something wrong, if I'm an idiot, or... ``` MailMessage msg = new MailMessage(); msg.To.Add("person1@example.com"); msg.To.Add("person2@example.com"); msg.To.Add("person3@example.com"); msg.To.Add("person4@example.com"); ``` Really only sends this email to 1 person, the last one. To add multiples I have to do this: ``` msg.To.Add("…

Accepted Answer

I wasn't able to replicate your bug:

```
var message = new MailMessage();

message.To.Add("user@example.com");
message.To.Add("user2@example.com");

message.From = new MailAddress("test@example.com");
message.Subject = "Test";
message.Body = "Test";

var client = new SmtpClient("localhost", 25);
client.Send(message);
```

Dumping the contents of the To: MailAddressCollection:

MailAddressCollection (2 items) DisplayName User Host Address

user example.com user@example.com user2 example.com user2@example.com

And the resulting e-mail as caught by smtp4dev:

```
Received: from mycomputername (mycomputername [127.0.0.1])
     by localhost (Eric Daugherty's C# Email Server)
     3/8/2010 12:50:28 PM
MIME-Version: 1.0
From: test@example.com
To: user@example.com, user2@example.com
Date: 8 Mar 2010 12:50:28 -0800
Subject: Test
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable

Test
```

Are you sure there's not some other issue going on with your code or SMTP server?

.Net System.Mail.Message adding multiple "To" addresses

Solution

Problem