控制台main函数中发起一个异步线程：

Question

GetDoubleNumericalHandler handler = new GetDoubleNumericalHandler(getDoubleNumerical.GetData);
IAsyncResult result = handler.BeginInvoke(new AsyncCallback(CallbackFunction), "AsycState:OK");
CallbackFunction是回调函数
但是测试发现回调函数是在异步线程中执行的，请问大神们有没有什么方法可以将回调函数插入到主线程中？

Answer 1

回调函数本来就是在调用方的线程中被执行的。若真想在主线程中得到异步的结果，应该用消息（SendMessage）而非回调。

Answer 2

可以通过线程池ThreadPool来解决，使用ThreadPool.QueueUserWorkItem(回调函数，object)，将参数封装在一个类的对象中，传给回调函数去执行。TheadPool的用法：1、创建一个ManualResetEvent的对象，就像一个信号灯，指示线程的挂起和执行；2、ManualResetEvent对象创建时，可以指定默认状态：true为有信号，false为无信号；3、调用Reset()方法重置状态；4、调用WaitOne()方法，使线程处于等待状态；5、调用Set()方法设置状态。using System;using System.Collections.Generic;using System.Text;using System.Threading;using System.Collections;namespace Demo{public class ParamObject{public int number;public ParamObject (int number){this.number = number;}}public class ThreadClass{public Hashtable aHashTable;public ManualResetEvent aManualResetEvent;public static int iCount = 0;public static int iMaxCount = 0;public ThreadClass(int maxCount){aHashTable = new Hashtable(maxCount);iMaxCount = maxCount;}public void ThreadRun(object aParamObject){Console.WriteLine("HashCode: {0}, Number in Object: {1}", Thread.CurrentThread.GetHashCode(), ((ParamObject)aParamObject).number);lock (aHashTable){if (!aHashTable.ContainsKey(Thread.CurrentThread.GetHashCode())){aHashTable.Add(Thread.CurrentThread.GetHashCode(), 0);}aHashTable[Thread.CurrentThread.GetHashCode()] = (int)aHashTable[Thread.CurrentThread.GetHashCode()] + 1;}Thread.Sleep(3000);Interlocked.Increment(ref iCount);if (iCount == iMaxCount){Console.WriteLine("Setting aManualResetEvent...");aManualResetEvent.Set();}}}class Program{public static void Main(string[] args){bool enableThreadPool = false;int iMaxCount = 20;ManualResetEvent aManualResetEvent = new ManualResetEvent(false);Console.WriteLine("Insert {0} items to Thread Pool.", iMaxCount);ThreadClass aThreadClass = new ThreadClass(iMaxCount);aThreadClass.aManualResetEvent = aManualResetEvent;// First, add an item to check if your system supports ThreadPool API function or not.try{ThreadPool.QueueUserWorkItem(new WaitCallback(aThreadClass.ThreadRun), new ParamObject(0));enableThreadPool = true;}catch (NotSupportedException ex){Console.WriteLine("Thread Pool API is not supported in this system.");enableThreadPool = false;}if (enableThreadPool){for (int i = 1; i < iMaxCount; i++){ThreadPool.QueueUserWorkItem(new WaitCallback(aThreadClass.ThreadRun), new ParamObject(i));}Console.WriteLine("Waiting for thread pool to drain");aManualResetEvent.WaitOne(Timeout.Infinite, true);Console.WriteLine("Thread Pool has been drained.");Console.WriteLine("Load threads info:");foreach (object key in aThreadClass.aHashTable.Keys){Console.WriteLine("Key: {0}, Value: {1}", key, aThreadClass.aHashTable[key]);}}Console.ReadLine();}}}&nbsp;