异步/计谋异常处理模式 [英] async/await exception handling pattern

问题描述

我在code以下反复出现的try / catch模式。使用try / catch块来处理调用orionProxy的方法时抛出的异常。

I have the following reoccurring try/catch pattern in my code. Using a try/catch block to handle any exceptions thrown when calling a method in orionProxy.

async private void doGetContacts()
{
    try {
        currentContacts = await orionProxy.GetContacts (); // call method in orionProxy
        ShowContacts (); // do something after task is complete
    }
    catch (Exception e) {
        orionProxy.HandleException (e); // handle thrown exception
    }
}

我想写的东西像下面这样。

What I would like to write is something like the following.

async private void doGetContacts()
{
    currentContacts = await orionProxy.CheckForException(orionProxy.GetContacts ());
    ShowContacts (); // do something after task is complete but shouldn't run on exception
}

任何指针/建议吗？我已经试过各种形式的操作/任务/ lambda表达式，但什么都不会正确地捕获异常orionProxy.CheckForException（？），所以ShowContacts不运行。

Any pointers/suggestions? I've tried various forms of Actions/Tasks/Lambdas but nothing will properly trap the exception in orionProxy.CheckForException(?) so ShowContacts doesn't run.

推荐答案

我不明白为什么这是行不通的，假设 GetContacts 是异步方法：

I don't see why it wouldn't work, assuming GetContacts is an async method:

public async Task<T> CheckForExceptionAsync<T>(Task<T> source)
{
  try
  {
    return await source;
  }
  catch (Exception ex)
  {
    HandleException(ex);
    return default(T);
  }
}

在一个侧面说明，您应该避免异步无效 （如我描述我在MSDN文章）和结束你的异步与异步后缀的方法名。

On a side note, you should avoid async void (as I describe in my MSDN article) and end your async method names with the Async suffix.

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