SmtpClient.Credentials Property (System.Net.Mail)

Credentials Property

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

SmtpClient..::.Credentials Property

Gets or sets the credentials used to authenticate the sender.

Namespace: System.Net.Mail
Assembly: System (in System.dll)

Syntax

Visual Basic (Declaration)

Public Property Credentials As ICredentialsByHost

Visual Basic (Usage)

Dim instance As SmtpClient
Dim value As ICredentialsByHost

value = instance.Credentials

instance.Credentials = value

public ICredentialsByHost Credentials { get; set; }

Visual C++

public:
property ICredentialsByHost^ Credentials {
    ICredentialsByHost^ get ();
    void set (ICredentialsByHost^ value);
}

JScript

public function get Credentials () : ICredentialsByHost
public function set Credentials (value : ICredentialsByHost)

Property Value

Type: System.Net..::.ICredentialsByHost
An ICredentialsByHost that represents the credentials to use for authentication; or nullNothingnullptra null reference (Nothing in Visual Basic) if no credentials have been specified.

Exceptions

Exception	Condition
InvalidOperationException	You cannot change the value of this property when an email is being sent.

Remarks

Some SMTP servers require that the client be authenticated before the server will send e-mail on its behalf. To use your default network credentials, you can set the UseDefaultCredentials to true instead of setting this property. If the UseDefaultCredentials property is set to false, then the value set in the Credentials property will be used for the credentials when connecting to the server. If the UseDefaultCredentials property is set to false and the Credentials property has not been set, then mail is sent to the server anonymously.

Credentials information can also be specified using the application and machine configuration files. For more information, see <mailSettings> Element (Network Settings). If information is specified using the Credentials property, this information overrides the configuration file settings.

Caution:
If you provide credentials for basic authentication, they are sent to the server in clear text. This can present a security issue because your credentials can be seen, and then used by others.

Examples

The following code example demonstrates setting the credentials used to send an e-mail.

        public static void CreateTestMessage1(string server, int port)
        {
            string to = "jane@contoso.com";
            string from = "ben@contoso.com";
            string subject = "Using the new SMTP client.";
            string body = @"Using this new feature, you can send an e-mail message from an application very easily.";
            MailMessage message = new MailMessage(from, to, subject, body);
            SmtpClient client = new SmtpClient(server, port);
            // Credentials are necessary if the server requires the client 
            // to authenticate before it will send e-mail on the client's behalf.
            client.Credentials = CredentialCache.DefaultNetworkCredentials;

      try {
              client.Send(message);
      }
            catch (Exception ex) {
              Console.WriteLine("Exception caught in CreateTestMessage1(): {0}", 
                    ex.ToString() );
      }              
        }

Visual C++

   static void CreateTestMessage1( String^ server, int port )
   {
      String^ to = L"jane@contoso.com";
      String^ from = L"ben@contoso.com";
      String^ subject = L"Using the new SMTP client.";
      String^ body = L"Using this new feature, you can send an e-mail message from an application very easily.";
      MailMessage^ message = gcnew MailMessage( from,to,subject,body );
      SmtpClient^ client = gcnew SmtpClient( server,port );

      // Credentials are necessary if the server requires the client 
      // to authenticate before it will send e-mail on the client's behalf.
      client->Credentials = CredentialCache::DefaultNetworkCredentials;

      //Display the properties on the service point.
      ServicePoint^ p = client->ServicePoint;
      Console::WriteLine( L"Connection lease timeout: {0}", p->ConnectionLeaseTimeout );
      client->Send( message );
      client->~SmtpClient();
   }

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0

Reference

SmtpClient Class

SmtpClient Members

System.Net.Mail Namespace