How to send EMail using C#

System.Net.Mail Namespace

The System.Net.Mail namespace contains classes used to send electronic mail to Simple Mail Transfer Protocol (SMTP) server for delivery.

Classes

1.       MailAddress: Represents the address of an electronic mail sender or recipient.

Inheritance Hierarchy:

System.Object

                System.Net.Mail.MailAddress

Constructors:

I.                    MailAddress(String emailAddress): Initializes a new instance of the MailAddress class using the specified address.

2.       MailMessage: Represents an e-mail message that can be sent using the SmtpClient class.

Inheritance Hierarchy:

System.Object

                System.Net.Mail.MailMessage

Constructors:

I.                    MailMessage(): Initializes an empty instance of the MailMessage class.

II.                  MailMessage(MailAddress from,  MailAddress to): Initializes a new instance of the MailMessage class by using the specified MailAddress class objects.

Properties:

I.                    AlternateViews: Gets the attachment collection used to store alternate forms of the message body.

II.                  Attachments: Gets the attachment collection to store data attached to this e-mail message.

III.                Bcc: Gets the address collection that contains the blind carbon copy (BCC) recipients for this e-mail message.

IV.                Body: Gets or sets the message body.

V.                  CC: Gets the address collection that contains the carbon copy (CC) recipients for this e-mail message.

VI.                From: Gets or sets the from address for this e-mail message.

VII.              IsBodyHtml: Gets or sets a value indicating whether the mail message body is in Html.

VIII.            Priority: Gets or sets the priority of this e-mail message.

IX.                ReplyTo: Obsolete. Gets or sets the ReplyTo address for the mail message.

X.                  Sender: Gets or sets the sender’s address for this e-mail message.

XI.                Subject: Gets or sets the subject line for this e-mail message.

XII.              To: Gets the address collection that contains the recipients of this e-mail message.

3.       Attachment: Represents an attachment to an e-mail.

Inheritance Hierarchy:

System.Object

                System.Net.Mail.AttachmentBase

                                System.Net.Mail.Attachment

Constructors:

I.                    Attachment(String filename): Initializes a new instance of the Attachment class with the specified content string.

Methods:

I.                    CreateAttachmentFromString(String filename, ContentType mimetype): Creates a mail attachment using the content from the specified string, and the specified ContentType.

4.       LinkedResource: Represents an embedded external resource in an email attachment, such as an image in an HTML attachment.

Inheritance Hierarchy:

System.Object

                System.Net.Mail.AttachmentBase

                                System.Net.Mail.LinkedResource

Constructors:

I.                    LinkedResource(String filename): Initializes a new instance of LinkedResource using the specified file name.

Properties:

I.                    ContentId:  Gets or Sets the MIME content ID for this attachment.

II.                  TransferEncoding:  Gets or Sets the encoding of this attachment.

Methods:

I.                    CreateLinkedResourceFromString(String filename): Creates a LinkedResource object from a string to be included in an email attachment as an embedded resource. The default media type is plain text, and the default content type is ASCII.

5.       AlternateView: Represents the format to view an email message.

Inheritance Hierarchy:

System.Object

                System.Net.Mail.AttachmentBase

                                System.Net.Mail.AlternateView

Constructors:

I.                    AlternateView(String filename, ContentType mimetype): Initializes a new instance of AlternateView with the specified file name and content type.

Properties:

I.                    ContentType:  Gets the Content type of this attachment.

Methods:

I.                    CreateAlternateViewFromString(String filename): Creates a AlternateView of an email message using the content specified in a String.

6.       SmtpClient: Allows applications to send e-mail by using the Simple Mail Transfer Protocol (SMTP).

Inheritance Hierarchy:

System.Object

                System.Net.Mail.SmtpClient

Constructors:

I.                    SmtpClient(): Initializes a new instance of the SmtpClient class by using configuration file settings.

II.                  SmtpClient(String smtpserver, Int32 port): Initializes a new instance of the SmtpClient class that sends e-mail by using the specified SMTP server and port.

Properties:

I.                    Credentials: Gets or sets the credentials used to authenticate the sender.

II.                  EnableSsl: Specify whether the SmtpClient uses Secure Sockets Layer(SSL) to encrypt the connection.

III.                Host: Gets or sets the name or IP address of the host used for SMTP transactions.

IV.                Port: Gets or sets the port used for SMTP transactions.

V.                  UseDefaultCredentials: Gets or sets a Boolean value that controls whether the DefaultCredentials are sent with requests.

VI.                DeliveryMethod: Specifies how outgoing email messages will be handled.

Methods:

I.                    Send(MailMessage): Sends the specified message to an SMTP server for delivery.

II.                  Send(String sender, String recipients, String subject, String message): Sends the specified e-mail message to an SMTP server for delivery. The message sender, recipients, subject, and message body are specified using String objects.

Events:

I.                    SendCompleted: Occurs when an asynchronous e-mail send operation completes.

7.       SmtpException: Represents the exception that is thrown when the SmtpClient is not able to complete a Send or SendAsync operation.

Inheritance Hierarchy:

System.Object

                System.Exception

                                System.Net.Mail.SmtpException

                                                System.Net.Mail.SmtpFailedRecipientException

8.       SmtpFailedRecipientException: Represents the eception that is thrown when the SmtpClient is not able to complete a Send or SendAsync operation to a particular recipient.

Inheritance Hierarchy:

System.Object

                System.Exception

                                System.Net.Mail.SmtpException

                                                System.Net.Mail.SmtpFailedRecipientException

                                                                System.Net.Mail.SmtpFailedRecipientsException

Enumerations:

1.       MailPriority: Specifies the priority to the MailMessage

Members:

I.                    Normal                 -              The email has normal priority

II.                  Low                        -              The email has low priority

III.                High                       -              The email has high priority

Web.config:

1.       <smtp>:  Configures the delivery method and from address for sending mails.

Syntax:                 <smtp

                                                                deliveryMethod = “method”

                                                                from = “fromAddress”> </smtp>

2.       <network>:  Configures the network options for external SMTP Server.

Syntax:                 <network

                                                defaultCredentials = “true | false”

                                                enableSsl = “true | false”

                                                host = “string”

                                                password = “string”

                                                port = “integer”

                                                username = “string” />

Example:

               

<configuration>

  <system.net>

    <mailSettings>

      <smtp

        deliveryMethod="Network"

        from="from.address@gmail.com">

        <network

          defaultCredentials="false"

          host="smtp.gmail.com"

          port="587"

          enableSsl="true"

          userName="from.address@gmail.com"

          password="password"/>

      </smtp>

    </mailSettings>

  </system.net>

</configuration>

Sample SMTP Server Settings:

1.       Gmail: 

Host	smtp.gmail.com
Port	587

2.       Yahoo:

Host	smtp.mail.yahoo.com
Port	995

Example:

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="SmtpClientWithoutWebConfig._Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

        Click the button to send the mail...

        <asp:Button Text="Send EMail" runat="server" ID="btnSendEMail"

            onclick="btnSendEMail_Click" />

        <br />

        <br />

        <asp:Label ID="lblMsg" runat="server"></asp:Label>

    </div>

    </form>

</body>

</html>

Default.aspx.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Net;

using System.Net.Mail;

namespace SmtpClientWithoutWebConfig

{

    public partial class _Default : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

        }

        protected void btnSendEMail_Click(object sender, EventArgs e)

        {

            SendEMail();

        }

        protected void SendEMail()

        {

            // declaring the email addresses...

            // from email address

            MailAddress fromAddress = new MailAddress("from.address@gmail.com");

            // to email address

            MailAddress toAddress = new MailAddress("to.address@gmail.com");

            // bcc email address

            MailAddress bccAddress = new MailAddress("bcc.address@gmail.com");

            // cc email address

            MailAddress ccAddress = new MailAddress("cc.address@gmail.com");

            // declaring the attachments...

            Attachment simpleAttachment = new Attachment(@"F:\SA.txt");

            // declaring the linked resources...

            LinkedResource simpleLinkedResource = new LinkedResource(@"F:\Desert.jpg");

            simpleLinkedResource.ContentId = "DesertImage";

            simpleLinkedResource.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;

            // declaring the alternate views...

            string strHtmlView = "<img src=cid:DesertImage height='200' width='200' /><br /><b>Hai...This mail is sent using C#</b>";

            AlternateView htmlView = AlternateView.CreateAlternateViewFromString(strHtmlView);

            htmlView.ContentType = new System.Net.Mime.ContentType("text/html");

            htmlView.LinkedResources.Add(simpleLinkedResource);

            // declaring the mail message...

            MailMessage msg = new MailMessage();

            msg.From = fromAddress;

            msg.To.Add(toAddress);

            msg.Bcc.Add(bccAddress);

            msg.CC.Add(ccAddress);

            msg.Subject = "Simple Mail";

            msg.AlternateViews.Add(htmlView);

            msg.Attachments.Add(simpleAttachment);

            msg.IsBodyHtml = true;

            msg.Priority = MailPriority.High;

            msg.Body = "Hai...This mail is sent using C#";

            // setting up the smtpclient and sending the mail...

            SmtpClient sc = new SmtpClient();

            sc.Host = "smtp.gmail.com";

            sc.Port = 587;

            sc.EnableSsl = true;

            sc.UseDefaultCredentials = false;

            sc.Credentials = new NetworkCredential(fromAddress.Address, "password");

            sc.DeliveryMethod = SmtpDeliveryMethod.Network;

            // now sending the mail...

            sc.Send(msg);

            lblMsg.Text = "Mail successfully sent to: " + toAddress.Address;

        }

    }

}