c# - 等待 IAsyncResult 函数直到完成

Question

我需要创建等待 IAsycnResult 方法直到完成的机制。我怎样才能做到这一点？

IAsyncResult result = _contactGroupServices.BeginDeleteContact(
  contactToRemove.Uri,
  ar =>
      {
      try
         {
           _contactGroupServices.EndDeleteContact(ar);
         }
      catch (RealTimeException rtex)
         {
            Console.WriteLine(rtex);
         }
      },
      null ); 

Answer 1

任务工厂有一个专门的方法：Task.Factory.FromAsync.

var task = Task.Factory.FromAsync(
    contactGroupServices.BeginDeleteContact(contactToRemove.Uri),
    ar =>
    {
        try
        {
            _contactGroupServices.EndDeleteContact(ar);
        }
        catch (RealTimeException rtex)
        {
            Console.WriteLine(rtex);
        }
    });

您可以通过调用阻塞直到它完成task.Wait，但在大多数情况下会死锁（例如，如果从 UI 线程调用）。

您可能希望将其放在异步方法中：

async Task M()
{
    ...
    await Task.Factory.FromAsync(
        contactGroupServices.BeginDeleteContact(contactToRemove.Uri),
        ar =>
        {
            try
            {
                _contactGroupServices.EndDeleteContact(ar);
            }
            catch (RealTimeException rtex)
            {
                Console.WriteLine(rtex);
            }
        });
    ...
}

Answer 2

我不知道这种方法的目标是什么_contactGroupServices.BeginDeleteContact。但是让我们尝试为它编写模板

Func<object> doWork = () =>
{
    return _contactGroupServices.BeginDeleteContact(<your parameters>)

};


AsyncCallback onWorkDone = (ar) =>
{
    //work done implementation
};

IAsyncResult asyncResult = doWork.BeginInvoke(onWorkDone, null); 

asyncResult.AsyncWaitHandle.WaitOne();

var result = doWork.EndInvoke(asyncResult);