Sending Emails in C#.Net

Hi Friends,
This post is regarding "Sending email", its configuration and samples.

How to Send a Message using C#.NET?
Once you create a message, you need to send it through an SMTP (Simple Message Transfer Protocol) server, which in turn will forward it to the recipient. In the .NET Framework, the SmtpClient class represents the SMTP server. Most of the time, sending a message is as simple as this sample code (where "smtp.contoso.com" is the name of the local SMTP server):
' VB
Dim m As MailMessage = New MailMessage _
("jane@contoso.com", _
"ben@contoso.com", _
"Quarterly data report.", _
"See the attached spreadsheet.")
Dim client As SmtpClient = New SmtpClient("smtp.contoso.com")
client.Send(m)
// C#
MailMessage m = new MailMessage
("jane@northrup.org",
"ben@northrup.org",
"Quarterly data report.",
"See the attached spreadsheet.");
SmtpClient client = new SmtpClient("smtp.contoso.com");
client.Send(m);

How to Configure Credentials
Next is to configure the Credentials. i.e.: UserName, Password, SMTP Settings.
To reduce spam, all SMTP servers should reject messages from unauthorized users when the message recipients are not hosted by the SMTP server. SMTP servers provided by ISPs typically determine whether a user is authorized based on the user's IP address; if you are part of the ISP's network, you are allowed to use the SMTP server.
Other SMTP servers (and some ISP SMTP servers) require users to provide a valid username and password. To use the default network credentials, set SmtpClient.UseDefaultCredentials to True. Alternatively, you can set SmtpClient.Credentials to CredentialCache.DefaultNetworkCredentials (in the System.Net namespace), as the following code demonstrates:
' VB
Dim client As SmtpClient = New SmtpClient("smtp.contoso.com")
client.Credentials = CredentialCache.DefaultNetworkCredentials
// C#
SmtpClient client = new SmtpClient("smtp.contoso.com");
client.Credentials = CredentialCache.DefaultNetworkCredentials;
To specify the username and password, create an instance of the System.Net.NetworkCredential class and use it to define SmtpClient.Credentials. The following example shows hard-coded credentials; however, you should always prompt the user for credentials:
' VB
Dim client As SmtpClient = New SmtpClient("smtp.contoso.com")
client.Credentials = New NetworkCredential("user", "password")
// C#
SmtpClient client = new SmtpClient("smtp.contoso.com");
client.Credentials = new NetworkCredential("user", "password");

Settings the Port No:
You might need to set the port no,

How to attach files?

To attach a file, add it to the MailMessage.Attachments AttachmentCollection by calling the MailMessage.Attachments.Add method. The simplest way to add a file is to specify the file name:
MailMessage m = new MailMessage();
m.Attachments.Add(new Attachment(@”C”\Tes.jpg”));
You can also specify MIME(Multipurpose Internet Mail Extensions) content type using the System.Net.Mime.MediaTypeNames enumeration. There are special MIME types for text and images, but you will typically specify MediaTypeNames.Application.Octet. The following code sample(which requires System.IO and System.Net.Mime in addition to System.Net.Mail) demonstrates how to use a Stream as a file attachment and how to specify the MIME type:
MailMessage m = new MailMessage();
Stream sr = new FileStream(@”C:\Test.txt”, FileMode.Open, FileAccess.Read);
m.Attachments.Add(new Attachment(sr, “testimage.txt”, MediaTypeNames.Application.Octet )

How to Create HTML E-mails?
To created an HTML e-mail message, supply HTML-tagged content for MailMessage.Body and set the MailMessage.IsBodyHtml attribute to True

Code Sample:

MailMessage m = new MailMessage();
m.From = new MailAddress("lance@contoso.com","Lance Trucker");
m.To.Add(new MailAddress("burke@contoso.com", "Burke Fewel"));
m.Subject = "Testing HTML";

//Specify an HTML message Body
m.Body = "HTML Tags...";
m.IsBodyHtml = true;

//send the message
SmtpClient client = new SmtpClient("smtp.contoso.com");
client.Send(m);