异步调用过程

2、在委托中加入函数：public int AsynCompute(ulong l, out ulong factorial)
AsynComputeCaller caller = new AsynComputeCaller(AsynCompute);

3、开始异步调用
ulong l = 30;
ulong lf;
IAsyncResult iResult = caller.BeginInvoke(l, out lf, null, null);

4.1、用IsCompleted
while (iResult.IsCompleted == false)
{
   // 主线程进行一些操作
   Thread.Sleep(10);
}

4.2、WaitOne（单个结果）
// 主线程进行一些操作
System.Threading.WaitHandle waiHand = iResult.AsyncWaitHandle;
waiHand.WaitOne();

4.3、WaitAll、WaitAny（多个结果）
// 主线程进行一些操作
System.Threading.WaitHandle.WaitAll(new System.Threading.WaitHandle[] { waiHand 1，waiHand 2});
WaitHandle.WaitAny(waitHandles,60000, false);

5、获取异步结果
int returnValue = caller.EndInvoke(out lf,iResult);