c# - AsyncCallback 通过引用变量取值

Question

我需要使用异步委托(delegate)调用一个函数，当我浏览 AsyncCallback 的教程时，我看到异步回调定义如下:

static void CallbackMethod(IAsyncResult result)
{
   // get the delegate that was used to call that
   // method
   CacheFlusher flusher = (CacheFlusher) result.AsyncState;

   // get the return value from that method call
   int returnValue = flusher.EndInvoke(result);

   Console.WriteLine("The result was " + returnValue);
}       

如果我可以从函数中获取返回值作为引用，请告诉我。例如:=我的函数格式为

void GetName(int id,ref string Name);

在这里，我通过引用变量获取函数的输出。如果我使用异步委托(delegate)调用此函数，我该如何读取回调函数的输出？

Answer 1

您需要将参数包装到一个对象中:

class User
{
    public int Id { get; set; }

    public string Name { get; set; }
}

void GetName(IAsyncResult result)
{
    var user = (User)result.AsyncState
    // ...
}

AsyncCallback callBack = new AsyncCallback(GetName);