c#之使用 smtp SendAsync 发送邮件

这就是当我需要发送电子邮件时出现错误的原因。但是自从给我的错误是这样的:

An asynchronous operation cannot be started at this time. Asynchronous operations may only be started within an asynchronous handler or module or during certain events in the Page lifecycle. If this exception occurred while executing a Page, ensure that the Page is marked <%@ Page Async="true" %>. This exception may also indicate an attempt to call an "async void" method, which is generally unsupported within ASP.NET request processing. Instead, the asynchronous method should return a Task, and the caller should await it.

我从 MVC 开始积累，并使用类来跟踪页面的 ie 区域。我使用 SendAsync 的原因恰恰是它发送电子邮件等的速度要快一些。

此错误仅在我尝试向用户发送电子邮件时发生。

public static void NewPassword(string mail, string name, string password) 
    { 
        MailDefinition oMailDefinition = new MailDefinition(); 
        oMailDefinition.BodyFileName = "~/MailList/emailskabelon/NewPassword.html"; 
        oMailDefinition.From = FromMail; 
 
        Dictionary<string, string> oReplacements = new Dictionary<string, string>(); 
        oReplacements.Add("<<navn>>", name); 
        oReplacements.Add("<<password>>", password); 
 
        System.Net.Mail.MailMessage oMailMessage = oMailDefinition.CreateMailMessage(mail, oReplacements, new LiteralControl()); 
        oMailMessage.Subject = NewpasswordTitle + WebsiteName; 
        oMailMessage.IsBodyHtml = true; 
 
        SmtpClient smtp = new SmtpClient(AzureApi); 
        System.Net.NetworkCredential netcred = new System.Net.NetworkCredential(AzureName, AzurePassword); 
        smtp.UseDefaultCredentials = false; 
        smtp.EnableSsl = true; 
 
        smtp.Credentials = netcred; 
        smtp.Port = Convert.ToInt32("25"); 
        smtp.DeliveryMethod = SmtpDeliveryMethod.Network; 
 
        using (var smtpClient = new SmtpClient()) 
        { 
            smtp.SendAsync(oMailMessage, null); 
        } 
    } 

我试过这样做:

public static async NewPassword(string mail, string name, string password) 
        { 
            .... 
            using (var smtpClient = new SmtpClient()) 
            { 
                await smtp.SendAsync(oMailMessage, null); 
            } 

我在这里看到:https://stackoverflow.com/a/35212320/7391454

请您参考如下方法:

将您的方法更改为:

public async Task SendEmail(string toEmailAddress, string emailSubject, string emailMessage) 
{ 
var message = new MailMessage(); 
message.To.Add(toEmailAddress); 
 
message.Subject = emailSubject; 
message.Body = emailMessage; 
 
using (var smtpClient = new SmtpClient()) 
{ 
    await smtpClient.SendMailAsync(message); 
} 
} 

然后这样调用它:

var task = SendEmail(toEmailAddress, emailSubject, emailMessage); 
var result = task.WaitAndUnwrapException(); 

看这里Asynchronously sending Emails in C#? 在这里 How to call asynchronous method from synchronous method in C#?