主线程等待子线程执行二

如果要执行的内容很多，但允许开的最大线程数固定，比如20个。要等待所有线程执行完毕后才能继续，可以参考如下代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using CDBDataMultiSync.Model;
using System.Threading;
using System.Threading.Tasks;

namespace CDBDataMultiSync.BLL
{
    /// <summary>
    /// 导入数据管理
    /// </summary>
    public class ImportDataManager
    {

        public void MultiImportMessage(List<Message> messageLists)
       {
          //创建线程等待委托列表
           //List<WaitHandle> waitHandles = new List<WaitHandle>();
           ThreadPool.SetMaxThreads(20, 20);
           int waitThreadCount= 0; int MaxThreadCount= 0;
           for (int i = 0; i < messageLists.Count;i++ )
           {
                //从线程池中获取一个线程来执行任务
               ThreadPool.QueueUserWorkItem(new WaitCallback(CreateThreadDoTask), messageLists[i]);
           }         
           //等待所有线程执行完毕
           while(true)
           {
             ThreadPool.GetAvailableThreads(out wth,out mth);
               if(waitThreadCount-MaxThreadCount==0)
               {
                   Console.WriteLine("空闲线程数{0},最大线程数{1}", wth, mth);
                   Console.WriteLine("全部执行完毕");
                   break;
               }
           }

       }

        public void CreateThreadDoTask(object msgObject)
        {
              Message msg = (Message)msgObject;
              ImportOneMessage(msg);
         }

        /// <summary>
        /// 多线程导入
        /// </summary>
        /// <param name="messageLists"></param>
        public void ImportOneMessage(Message msg)
        {
            Console.WriteLine("正在执行" + msg.BussinessName);

            int wth = 0; int mth = 0;
            ThreadPool.GetAvailableThreads(out wth, out mth);
            Console.WriteLine("空闲线程数{0},最大线程数{1}", wth, mth);

            Thread.Sleep(3000);
            Console.WriteLine("执行完毕=====" + msg.BussinessName);
            Console.WriteLine("空闲线程数{0},最大线程数{1}", wth, mth);
        }

    }
}