[英]what is the difference between these two methods?
system.net.mail.smtpclient
has two methods for which I am very confused. system.net.mail.smtpclient
有两种方法,我很困惑。
1 . 1。 SendAsync(MailMessage, Object) SendAsync(MailMessage,Object)
Sends the specified e-mail message to an SMTP server for delivery. This method does not block the calling thread and allows the caller to pass an object to the method that is invoked when the operation completes.
-MSDN -MSDN
2 . 2。 SendMailAsync(MailMessage) SendMailAsync(MAILMESSAGE)
Sends the specified message to an SMTP server for delivery as an asynchronous operation.
-MSDN -MSDN
Notice that the names of two methods are different so it is not an overload. 请注意,两个方法的名称不同,因此它不是重载。 What exactly is the difference here? 这有什么区别?
I am looking for very clear answer as the description given by MSDN for both methods is very ambiguous (at least for me it is.) 我正在寻找非常明确的答案,因为MSDN对这两种方法的描述非常模糊(至少对我来说是这样)。
The difference is one SendMailAsync
uses the new async/await
technology and the other uses the old callback technology. 区别在于SendMailAsync
使用新的async/await
技术,而另一种使用旧的回调技术。 And more importantly, the Object
that's passed is simply passed into the event handler as the userState
when the method completes. 更重要的是,传递的Object
只是在方法完成时作为userState
传递给事件处理程序。
Firstly, they both work asynchronously. 首先,它们都是异步工作的。
However, SendAsync
has existed since .NET 2. In order to maintain backwards compatiblity whilst supporting the new Tasks system SendMailAsync
was added. 但是,自.NET 2以来, SendAsync
已经存在。为了在支持新任务系统的同时保持向后兼容性,添加了SendMailAsync
。
SendMailAsync
returns a Task
rather than void
and allows the SmtpClient
to support the new async
and await
functionality if required. SendMailAsync
返回一个Task
而不是void
并允许SmtpClient
支持新的async
和await
功能(如果需要)。
SendMailAsync
是SendAsync
的简单TAP包装器更多信息: SmtpClient.SendMailAsync方法线程安全吗?
//SendAsync
public class MailHelper
{
public void SendMail(string mailfrom, string mailto, string body, string subject)
{
MailMessage MyMail = new MailMessage();
MyMail.From = new MailAddress(mailfrom);
MyMail.To.Add(mailto);
MyMail.Subject = subject;
MyMail.IsBodyHtml = true;
MyMail.Body = body;
MyMail.Priority = MailPriority.Normal;
SmtpClient smtpMailObj = new SmtpClient();
/*Setting*/
object userState = MyMail;
smtpMailObj.SendCompleted += new SendCompletedEventHandler(SmtpClient_OnCompleted);
try
{
smtpMailObj.SendAsync(MyMail, userState);
}
catch (Exception ex) { /* exception handling code here */ }
}
public static void SmtpClient_OnCompleted(object sender, AsyncCompletedEventArgs e)
{
//Get the Original MailMessage object
MailMessage mail = (MailMessage)e.UserState;
//write out the subject
string subject = mail.Subject;
if (e.Cancelled)
{
Console.WriteLine("Send canceled for mail with subject [{0}].", subject);
}
if (e.Error != null)
{
Console.WriteLine("Error {1} occurred when sending mail [{0}] ", subject, e.Error.ToString());
}
else
{
Console.WriteLine("Message [{0}] sent.", subject);
}
}
//
}
//SendMailAsync
public class MailHelper
{
//
public async Task<bool> SendMailAsync(string mailfrom, string mailto, string body, string subject)
{
MailMessage MyMail = new MailMessage();
MyMail.From = new MailAddress(mailfrom);
MyMail.To.Add(mailto);
MyMail.Subject = subject;
MyMail.IsBodyHtml = true;
MyMail.Body = body;
MyMail.Priority = MailPriority.Normal;
using (SmtpClient smtpMailObj = new SmtpClient())
{
/*Setting*/
try
{
await smtpMailObj.SendMailAsync(MyMail);
return true;
}
catch (Exception ex) { /* exception handling code here */ return false; }
}
}
}
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