如何将 SendGrid 响应状态作为字符串获取？

Question

我在从 SendGrid 检索 HTTP 响应代码，然后根据该响应更新标签时遇到问题。由于 SendGrid 调用使​​用异步方法，我无法返回 response.statuscode；

这是我的代码：

 protected void BtnSend_Click(object sender, EventArgs e)
        {
                lblmsg.InnerText = SendMail(txtEmailId.Text.ToString(), 
                txtMessage.Text.ToString());  //------------

        }




        private String SendMail(String EmailId, String Message)
        {
            var status="";
           Execute(EmailId, Message).Wait();
                  return status;  
        }



   async Task Execute(String EmailId, String Message)
        {
            var apiKey = "abcdefghijklmnopqrstuvwxyz1234567890";
            var client = new SendGridClient(apiKey);
            var from = new EmailAddress("myemail@gmail.com", "Sender");
            var subject = "Testing Email";
            var to = new EmailAddress(EmailId, "Reciever");
            var plainTextContent = "You have recieved this message from me";
            var htmlContent = Message + "<br><i>-Message sent by me</i>";
            var msg = MailHelper.CreateSingleEmail(from, to, subject, plainTextContent, htmlContent);
            var response = await client.SendEmailAsync(msg).ConfigureAwait(false);
            var status = response.StatusCode;

        }

Answer 1

您的方法不允许返回值，因为您将其声明为async Task。这意味着它是一个不返回任何内容的 async 方法（它只是返回一个 Task 以便调用者知道它何时完成，但没有实际值）。

如果您想从async 方法返回某些内容，则需要使用Task<T> 返回类型，其中T 是您要返回的值的类型。

所以在这种情况下，应该是：

async Task<HttpStatusCode> Execute(String EmailId, String Message)

那你可以return response.StatusCode

这里有一些额外的阅读材料可以帮助你更好地理解async 代码：

• Asynchronous programming
• The Task asynchronous programming model in C#
• Async in depth

Answer 2

要从异步方法返回值，必须等待它。请参阅下面的示例方法调用：

private async Task<System.Net.HttpStatusCode> Execute(String EmailId, String Message)
        {
            var apiKey = "abcdefghijklmnopqrstuvwxyz1234567890";
            var client = new SendGridClient(apiKey);
            var from = new EmailAddress("myemail@gmail.com", "Sender");
            var subject = "Testing Email";
            var to = new EmailAddress(EmailId, "Reciever");
            var plainTextContent = "You have recieved this message from me";
            var htmlContent = Message + "<br><i>-Message sent by me</i>";
            var msg = MailHelper.CreateSingleEmail(from, to, subject, plainTextContent, htmlContent);
            var response = await client.SendEmailAsync(msg).ConfigureAwait(false);
            return response.StatusCode;

        }

private async Task GetStatusCodeExample(String EmailId, String Message)
{
    var statusCode = await Execute(EmailId, Message);
}

---

编辑：

更新您的代码以使用以下内容以及上述更新的 Execute 方法：

protected void BtnSend_Click(object sender, EventArgs e)
{
     lblmsg.InnerText = SendMail(txtEmailId.Text.ToString(), 
     txtMessage.Text.ToString());  //------------


private String SendMail(String EmailId, String Message)
{
     var task = Execute(EmailId, Message);
     task.Wait();
     return ((int)task.Result).ToString();  
}