Net System Mail Message adding multiple To addresses

Question

EDIT   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 domain com    msg To Add  person2 domain com    msg To Add  person3 domain com    msg To Add  person4 domain com      Really only sends this email to 1 person  the last one   To add multiples I have to do this   msg To Add  person1 domain com person2 domain com person3 domain com person4 domain com      I don t get it   I thought I was adding multiple people to the To address collection  but what I was doing was replacing it   I think I just realized my error -- to add one item to the collection  use      To Add new MailAddress  person domain com     If you use just a string  it replaces everything it had in its list  EDIT   Other people have tested and are not seeing this behavior   This is either a bug in my particular version of the framework  or more likely  an idiot maneuver by me     Ugh   I d consider this a rather large gotcha   Since I answered my own question  but I think this is of value to have in the stackoverflow archive  I ll still ask it   Maybe someone even has an idea of other traps that you can fall into

User · Answer

Thanks for spotting this I was about to add strings thinking the same as you that they'd get added to end of collection. It appears the params are:

msg.to.Add(<MailAddress>) adds MailAddress to the end of the collection
msg.to.Add(<string>) add a list of emails to the collection

Slightly different actions depending on param type, I think this is pretty bad form i'd have prefered split methods AddStringList of something.

User · 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

User · Answer

using System  using System Collections Generic  using System IO  using System Linq  using System Net Mail  using System Web   namespace HMS HtmlHelper       public class SendmailHelper                 Created SendEMail method for sendiing mails to users          public bool SendEMail string FromName  string ToAddress  string Subject  string Message                        bool valid  false              try                               string smtpUserName   System Configuration ConfigurationManager AppSettings  smtpusername   ToString                    string smtpPassword   System Configuration ConfigurationManager AppSettings  smtppassword   ToString                    MailMessage mail   new MailMessage                      mail From   new MailAddress smtpUserName  FromName                   mail Subject   Subject                  mail To Add FormatMultipleEmailAddresses ToAddress                      mail To Add ToAddress                   mail Body   Message ToString                    mail IsBodyHtml   true                  SmtpClient smtp   new SmtpClient                    smtp Port   Convert ToInt32 System Configuration ConfigurationManager AppSettings  smtpserverport                     smtp Host   System Configuration ConfigurationManager AppSettings  SmtpServer                      smtp Credentials   new System Net NetworkCredential smtpUserName  smtpPassword                   smtp EnableSsl   Convert ToBoolean System Configuration ConfigurationManager AppSettings  ssl                       smtp Send mail                   valid   true                             catch  Exception ex                                valid  false                              return valid                       public string FormatMultipleEmailAddresses string emailAddresses                        var delimiters   new                              var addresses   emailAddresses Split delimiters  StringSplitOptions RemoveEmptyEntries                return string Join      addresses

User · Answer

Add multiple System MailAdress object to get what you want

User · Answer

private string FormatMultipleEmailAddresses string emailAddresses              var delimiters   new                        var addresses   emailAddresses Split delimiters  StringSplitOptions RemoveEmptyEntries          return string Join      addresses           Now you can use it like   var mailMessage   new MailMessage    mailMessage To Add FormatMultipleEmailAddresses  test gmail com john rediff com prashant mail com

User · Answer

Put in addresses this code   objMessage To Add    addresses      email1 yahoo com   email2 aol com   email3 gmail com

User · Answer

You could try putting the e-mails into a comma-delimited string   person1 domain com  person2 domain com     C    ArrayList arEmails   new ArrayList    arEmails Add  person1 domain com    arEmails Add  person2 domain com                     string strEmails   string Join       arEmails     VB NET if you re interested   Dim arEmails As New ArrayList arEmails Add  person1 domain com   arEmails Add  person2 domain com    Dim strEmails As String   String Join       arEmails

User · Answer

You can do this either with multiple System Net Mail MailAddress objects or you can provide a single string containing all of the addresses separated by commas

[asp.net] .Net System.Mail.Message adding multiple "To" addresses

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