C# BeginInvoke EndInvoke

如遇到以下两种需求时，可以试试 BeginInvoke 方法

1.某些时候需要开线程处理，需要主线程子线程配合完成

1-1.投票

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

namespace InvokeTest
{
    class Program
    {
        static int TakeAWhile(int data, int SleepMillionSeconds)
        {
            Console.WriteLine("TakesAWhile started");
            Thread.Sleep(SleepMillionSeconds);
            Console.WriteLine("TakesAWhile end");
            return ++data;
        }

        public delegate int TakesAWhileDelegate(int data, int SleepMillionSeconds);

        static void Main(string[] args)
        {
            TakesAWhileDelegate d1 = TakeAWhile;

            IAsyncResult asyncResult = d1.BeginInvoke(1, 3000, null, null);

            while(!asyncResult.IsCompleted)
            {
                //异步未完成，主线程执行
                Console.WriteLine(".");
                Thread.Sleep(500);
            }

            int result = d1.EndInvoke(asyncResult);
            Console.WriteLine("result: {0}", result);
            Console.ReadKey();
        }
    }
}

结果：

 

1-2.等待句柄

 

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

namespace InvokeTest
{
    class Program
    {
        static int TakeAWhile(int data, int SleepMillionSeconds)
        {
            Console.WriteLine("TakesAWhile started");
            Thread.Sleep(SleepMillionSeconds);
            Console.WriteLine("TakesAWhile end");
            return ++data;
        }

        public delegate int TakesAWhileDelegate(int data, int SleepMillionSeconds);

        static void Main(string[] args)
        {
            TakesAWhileDelegate d1 = TakeAWhile;

            IAsyncResult asyncResult = d1.BeginInvoke(1, 3000, null, null);

            while(true)
            {
                //异步未完成，主线程执行
                Console.WriteLine(".");
                if(asyncResult.AsyncWaitHandle.WaitOne(500, false))
                {
                    Console.WriteLine("Can get the result now.");

                    break;
                }     
            }

            int result = d1.EndInvoke(asyncResult);
            Console.WriteLine("result: {0}", result);
            Console.ReadKey();
        }
    }
}

结果：

 

1-3.回调函数

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace InvokeTest
{
    class Program
    {
        static int TakeAWhile(int data, int SleepMillionSeconds)
        {
            Console.WriteLine("TakesAWhile started");
            Thread.Sleep(SleepMillionSeconds);
            Console.WriteLine("TakesAWhile end");
            return ++data;
        }

        static void TakeAWhileComplete(IAsyncResult asyncResult)
        {
            if (asyncResult == null) throw new ArgumentNullException("asyncResult");

            TakesAWhileDelegate d1 = asyncResult.AsyncState as TakesAWhileDelegate;
            Trace.Assert(d1 != null, "Invalid object type");

            int result = d1.EndInvoke(asyncResult);
            Console.WriteLine("result: {0}", result);

        }

        public delegate int TakesAWhileDelegate(int data, int SleepMillionSeconds);

        static void Main(string[] args)
        {
            TakesAWhileDelegate d1 = TakeAWhile;

            d1.BeginInvoke(1, 3000, TakeAWhileComplete, d1);

            for(int i = 0; i < 15; i++)
            {
                //异步未完成，主线程执行
                Console.WriteLine(".");
                Thread.Sleep(500);
            }
            
            Console.ReadKey();
        }
    }
}

结果：

 

Lambda表达式写法

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace InvokeTest
{
    class Program
    {
        static int TakeAWhile(int data, int SleepMillionSeconds)
        {
            Console.WriteLine("TakesAWhile started");
            Thread.Sleep(SleepMillionSeconds);
            Console.WriteLine("TakesAWhile end");
            return ++data;
        }

        public delegate int TakesAWhileDelegate(int data, int SleepMillionSeconds);

        static void Main(string[] args)
        {
            TakesAWhileDelegate d1 = TakeAWhile;

            d1.BeginInvoke(1, 3000,

                //lambda表达式
                asyncResult => 
                {
                    int result = d1.EndInvoke(asyncResult);
                    Console.WriteLine("result: {0}", result);
                }, 
                d1);

            for(int i = 0; i < 15; i++)
            {
                //异步未完成，主线程执行
                Console.WriteLine(".");
                Thread.Sleep(500);
            }
            
            Console.ReadKey();
        }
    }
}

结果：

 

2.需要先执行完主线程，再执行子线程

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;


namespace WpfBeginInvokeTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            this.Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            //new Action(() =>
            //{
            //    Console.WriteLine("new child thread and run child thread");
            //}
            //).BeginInvoke(null, null);

            Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
            {
                Console.WriteLine("new child thread and run main thread");
            }));

            int i = 0;

            while (true)
            {
                i++;

                if (i > 100000000)
                    break;
            }

            Console.WriteLine("not new child thread and run main thread");

            //new Action(() =>
            //{
            //    Console.WriteLine("not new child thread and run main thread");
            //}
            //).Invoke();


            


            //Dispatcher.CurrentDispatcher.Invoke(DispatcherPriority.Background, new Action(() => 
            //{
            //    Console.WriteLine("not new child thread and run main thread");
            //}));
        }
    }
}

结果：

 注：要设置一下，即时窗口才可以显示