в ASP.NET.txt

Решение:

Пример с объяснениями

protected void Button1_Click(object sender, EventArgs e)
{
// SendMailMessage("fromAddress@yourdomain.com", "toAddress@yourdomain.com", "bccAddress@yourdomain.com", 
// "ccAddress@yourdomain.com", "Sample Subject", "Sample body of text for mail message");
SendMailMessage("seminar222@rudensoft.ru", "hecrus@mail.ru", "", 
"hecruss@gmail.com", "Привет с Infobox", "Это тело письма");
Response.Write("Success");
}

1. SendMailMessage – функция та же
2. В поле from надо указывать любой ящик, но в этого же домена, например xyz@rudensoft.ru(домен как в параметре smtp from)
Настройки веб-конфиг:

<system.net>
<mailSettings>
<smtp from="seminar@rudensoft.ru" deliveryMethod="Network">
<network host="mail.infobox.ru" password="xxxxx" port="25" userName="seminar@rudensoft.ru" />
</smtp>
</mailSettings>
</system.net>

Вызов функции:

MailHelper.SendMailMessage("fromAddress@yourdomain.com", "toAddress@yourdomain.com", "bccAddress@yourdomain.com", "ccAddress@yourdomain.com", "Sample Subject", "Sample body of text for mail message")

{
/// <summary>
/// Sends an mail message
/// </summary>
/// <param name="from">Sender address</param>
/// <param name="to">Recepient address</param>
/// <param name="bcc">Bcc recepient</param>
/// <param name="cc">Cc recepient</param>
/// <param name="subject">Subject of mail message</param>
/// <param name="body">Body of mail message</param>
MailHelper.cs

using System.Net.Mail;

public class MailHelper

public static void SendMailMessage(string from, string to, string bcc, string cc, string subject, string body)
{
// Instantiate a new instance of MailMessage
MailMessage mMailMessage = new MailMessage();
// Set the sender address of the mail message
mMailMessage.From = new MailAddress(from);
// Set the recepient address of the mail message
mMailMessage.To.Add(new MailAddress(to));

// Check if the bcc value is null or an empty string
if ((bcc != null) && (bcc != string.Empty))
{
// Set the Bcc address of the mail message
mMailMessage.Bcc.Add(new MailAddress(bcc));
}
// Check if the cc value is null or an empty value
if ((cc != null) && (cc != string.Empty))
{
// Set the CC address of the mail message
mMailMessage.CC.Add(new MailAddress(cc));
} // Set the subject of the mail message
mMailMessage.Subject = subject;
// Set the body of the mail message
mMailMessage.Body = body;

// Set the format of the mail message body as HTML
mMailMessage.IsBodyHtml = true;
// Set the priority of the mail message to normal
mMailMessage.Priority = MailPriority.Normal;

// Instantiate a new instance of SmtpClient
SmtpClient mSmtpClient = new SmtpClient();
// Send the mail message
mSmtpClient.Send(mMailMessage);
}
}

MailHelper.vb

Imports System.Net.Mail

Public Class MailHelper
<summary>
Sends an mail message
</summary>
<param name="from">Sender address</param>
<param name="recepient">Recepient address</param>
<param name="bcc">Bcc recepient</param>
<param name="cc">Cc recepient</param>
<param name="subject">Subject of mail message</param>
<param name="body">Body of mail message</param>

Public Shared Sub SendMailMessage(ByVal from As String, ByVal recepient As String, ByVal bcc As String, ByVal cc As String, ByVal subject As String, ByVal body As String)
' Instantiate a new instance of MailMessage
Dim mMailMessage As New MailMessage()

' Set the sender address of the mail message
mMailMessage.From = New MailAddress(from)
' Set the recepient address of the mail message
mMailMessage.To.Add(New MailAddress(recepient))

' Check if the bcc value is nothing or an empty string
If Not bcc Is Nothing And bcc <> String.Empty Then
' Set the Bcc address of the mail message
mMailMessage.Bcc.Add(New MailAddress(bcc))
End If

' Check if the cc value is nothing or an empty value
If Not cc Is Nothing And cc <> String.Empty Then
' Set the CC address of the mail message
mMailMessage.CC.Add(New MailAddress(cc))
End If

' Set the subject of the mail message
mMailMessage.Subject = subject
' Set the body of the mail message
mMailMessage.Body = body

' Set the format of the mail message body as HTML
mMailMessage.IsBodyHtml = True
' Set the priority of the mail message to normal
mMailMessage.Priority = MailPriority.Normal

' Instantiate a new instance of SmtpClient
Dim mSmtpClient As New SmtpClient()
' Send the mail message
mSmtpClient.Send(mMailMessage)
End Sub
End Class

Web.config

<?xml version="1.0"?>
<configuration>
<system.net>
<mailSettings>
<smtp from="defaultEmail@yourdomain.com">
<network host="smtp.yourdomain.com" port="25" userName="yourUserName" password="yourPassword"/>
</smtp>
</mailSettings>
</system.net>
</configuration>