static void Main(string[] args)
{
AsyncSum asum = Sum;
asum.BeginInvoke(100, (IAsyncResult ar) => { Console.WriteLine(asum.EndInvoke(ar)); }, null);
Console.ReadKey();
}
private static void FooCallBack(IAsyncResult ar)
{
AsyncSum caller = (AsyncSum)ar.AsyncState;; //获得BeginInvoke第4个参数
int number = caller.EndInvoke(ar); //获取运算的结果
}