从 Task.Run C# 中的 try/catch 返回异常

Question

我正在尝试使用网络表单上的按钮来处理将用户添加到邮件黑猩猩的过程。我有两个函数...一个按钮函数调用调用 API 的异步函数。

public class MailChimpResponse
{
    public bool IsSuccessful;
    public string ReponseMessage;
}

public void SubscribeEmail(object Sender, EventArgs e)
{
    var mcResponse = SubscribeEmailAsync();
    var result = mcResponse.Result;

    if (result.IsSuccessful == true)
    {
        lblSuccess.Text = result.ReponseMessage;
        pnlSuccess.Visible = true;
    }
    else
    {
        lblError.Text = result.ReponseMessage;
        pnlError.Visible = false;
    }
}

public async Task<MailChimpResponse> SubscribeEmailAsync()
{
    IMailChimpManager mailChimpManager = new MailChimpManager(ConfigurationManager.AppSettings["testing"]);
    MailChimpResponse mcResponse = new MailChimpResponse();
    var listId = "xxxxxxxxx";

    return await Task.Run(() =>
    {
        try
        {
            var mailChimpListCollection = mailChimpManager.Members.GetAllAsync(listId).ConfigureAwait(false);

            mcResponse.IsSuccessful = true;
            mcResponse.ReponseMessage = "Success!";
        }
        catch (AggregateException ae)
        {
            mcResponse.IsSuccessful = false;
            mcResponse.ReponseMessage = ae.Message.ToString();
        }

        return mcResponse;
    });

目前填充“var mailChimpListCollection”的行应该失败并抛出异常（我可以通过 Intellisense 看到它）但是它继续尝试而不是陷入 CATCH。这只会使每个调用看起来都成功，即使它不是。我在这里错过了什么？

Answer 1

根据您的描述，您正尝试根据mailChimpManager.Members.GetAllAsync(listId) 调用的结果从SubscribeEmailAsync 方法返回响应。 由于GetAllAsync 方法是一个异步方法，它不是返回成员列表，而是返回一个跟踪结果检索工作的任务。你真的错过了等待，你根本不需要人工的Task.Run。这里我将如何重写SubscribeEmailAsync 方法：

public async Task<MailChimpResponse> SubscribeEmailAsync()
{
    IMailChimpManager mailChimpManager = new MailChimpManager(ConfigurationManager.AppSettings["testing"]);
    MailChimpResponse mcResponse = new MailChimpResponse();
    var listId = "xxxxxxxxx";

    try
    {
        var mailChimpListCollection = await mailChimpManager.Members.GetAllAsync(listId).ConfigureAwait(false);

        mcResponse.IsSuccessful = true;
        mcResponse.ReponseMessage = "Success!";
    }
    catch (AggregateException ae)
    {
        mcResponse.IsSuccessful = false;
        mcResponse.ReponseMessage = ae.Message.ToString();
    }

    return mcResponse;
}

希望这会有所帮助。