MailAddress类有两个参数

第1个参数：发送者的邮箱

第2个参数：发送者的签名

示例：

MailMessage message = new MailMessage();
message.From = new MailAddress(sender, signature);
message.To.Add(recipient);

完整代码：(参照动软代码生成的MailSend.cs)

public static void Send(string server, string sender, string signature, string recipient, string subject,     string body, bool isBodyHtml, Encoding encoding, bool isAuthentication, params string[] files)

{

SmtpClient smtpClient = new SmtpClient(server);

//MailMessage message = new MailMessage(sender, recipient);

MailMessage message = new MailMessage();

message.From = new MailAddress(sender, signature);

message.To.Add(recipient);

message.IsBodyHtml = isBodyHtml;

message.SubjectEncoding = encoding;

message.BodyEncoding = encoding;

message.Subject = subject;

message.Body = body;

message.Attachments.Clear();

if (files != null && files.Length != 0)

{

for (int i = 0; i < files.Length; ++i)

{

　　Attachment attach = new Attachment(files[i]);

message.Attachments.Add(attach);

}

}

if (isAuthentication == true)

{

　　smtpClient.Credentials = new NetworkCredential(SmtpConfig.Create().SmtpSetting.User, SmtpConfig.Create().SmtpSetting.Password);

}

smtpClient.Send(message);

}