queueuserworkitem如何创建线程

C# 多线程的使用。如何使用多线程？

你用线程池(ThreadPool)可以实现，也可以用线程(Thread)实现 for (int i = 0; i < int.Parse(times); i++) //number of threads { //Console.WriteLine("thread i = " + i); //Thread oThread = new Thread(new ParameterizedThreadStart(Beta)); bool FIL = fi == "1" ? true :false; para p = new para { Finished = (i == int.Parse(times) - 1), Xml = doc.InnerXml, URL = url, num_msgs_processed = i, num_msgs_sent = i, FI = FIL }; // Start the thread //oThread.Start(p); //oThread.Join(); ThreadPool.QueueUserWorkItem(Beta, p); }

c# Socket 多线程例子

使用ThreadStart委托来衍生三个新线程

using System; using System.Threading; namespace ThreadStartSampleCS { class Program { static void Main() { Thread newThread; ThreadStart threadMethod = new ThreadStart(DoWork); for (int counter = 1; counter < 4; counter++) { Console.WriteLine("Starting Thread {0}", counter); newThread = new Thread(threadMethod); newThread.Name = counter.ToString(); newThread.Start(); } } static void DoWork() { for (int counter = 1; counter < 11; counter++) { Console.WriteLine("Thread {0}: iteration {1}", Thread.CurrentThread.Name, counter); Thread.Sleep(1); } } } } 使用ParameterizedThreadStart委托来衍生三个新线程 using System; using System.Threading; namespace ParameterizedThreadStartSampleCS { class Program { static void Main() { Thread newThread; ParameterizedThreadStart threadMethod = new ParameterizedThreadStart(DoWork); for (int counter = 1; counter < 4; counter++) { Console.WriteLine("Starting Thread {0}", counter); newThread = new Thread(threadMethod); newThread.Name = counter.ToString(); newThread.Start(5); } } static void DoWork(object iterations) { for (int counter = 1; counter < (int)iterations + 1; counter++) { Console.WriteLine("Thread {0}: iteration {1}", Thread.CurrentThread.Name, counter); Thread.Sleep(1); } } } } 使用ThreadPool类从线程池中启动线程 using System; using System.Threading; namespace ThreadPoolSampleCS { class Program { static void Main(string[] args) { ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc)); Console.WriteLine("Main thread starts"); Thread.Sleep(10000); Console.WriteLine("Main thread exits."); } static void ThreadProc(Object stateInfo) { Console.WriteLine("Hello from the thread pool. I will count from 1 to 100"); for (int counter = 1; counter < 101; counter++) { Console.WriteLine(counter); Thread.Sleep(500); } } } } 实现IAsyncResult接口和AsyncCallback委托 using System; using System.Threading; namespace AsynCallbackSampleCS { class Program { delegate int IntAsyncDelegate(int number); static IntAsyncDelegate aDelegate; static int i(int number) { if (number < 1) return 0; else if (number == 1 || number == 2) return number; else return i(number - 2) + i(number - 1); } static void DisplayResult(IAsyncResult ar) { int result = aDelegate.EndInvoke(ar); Console.WriteLine("Elemet number {0} in the i series is {1}", ar.AsyncState.ToString(), result); } static void Main(string[] args) { aDelegate = new IntAsyncDelegate(i); AsyncCallback callback = new AsyncCallback(DisplayResult); Console.Write("Enter a number: "); int number = int.Parse(Console.ReadLine()); aDelegate.BeginInvoke(number, callback, number); Console.WriteLine("wait while we process your request"); Thread.Sleep(5000); } } } 通过异步调用迁移线程的执行上下文 using System; using System.Collections.Generic; using System.Runtime.InteropServices; using System.Security.Principal; using System.Threading; namespace ExecutionHostSampleCS { class Program { [DllImport("advapi32.dll")] private static extern bool LogonUser( String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, out IntPtr phToken); static void Main() { System.IntPtr pToken; //请将LogonUser方法中的用户名、域名、密码替换成可以登陆本机的值。

if (LogonUser("用户名", "域名", "密码", 2, 0, out pToken)) { WindowsIdentity.Impersonate(pToken); DisplayContext("Main"); ThreadPool.QueueUserWorkItem(Callback, null); ExecutionContext ec = ExecutionContext.Capture(); ExecutionContext.SuppressFlow(); ThreadPool.QueueUserWorkItem(Callback, null); ContextCallback cb = new ContextCallback(Callback); ExecutionContext.Run(ec, cb, 0); ThreadPool.QueueUserWorkItem(Callback, null); ExecutionContext.RestoreFlow(); ThreadPool.QueueUserWorkItem(Callback, null); pToken = IntPtr.Zero; } Console.ReadLine(); } static void Callback(object o) { DisplayContext("Callback"); } static void DisplayContext(string s) { System.Console.WriteLine(s + " Thread#{0} Current user is {1}", Thread.CurrentThread.ManagedThreadId, WindowsIdentity.GetCurrent().Name); } } } 实现SynchronizationContext类和SendOrPostCallback委托 using System; using System.Threading; namespace SynchronizationContextSampleCS { class ount { public decimal balance; public void Deposit(decimal amount) { balance += amount; } public void Withdraw(decimal amount) { balance -= amount; } } class Program { static ount ount; static void Main(string[] args) { ount = new ount(); SendOrPostCallback deposit = new SendOrPostCallback(Deposit); SendOrPostCallback withdraw = new SendOrPostCallback(Withdraw); SynchronizationContext ctx = new SynchronizationContext(); ctx.Post(deposit, 500); ctx.Post(withdraw, 500); Console.ReadLine(); } static void Withdraw(object state) { Console.WriteLine("Withdraw: current balance = {0:C}", ount.balance); ount.Withdraw(decimal.Parse(state.ToString())); Console.WriteLine("Withdraw: new balance = {0:C}", ount.balance); } static void Deposit(object state) { Console.WriteLine("Withdraw: current balance = {0:C}", ount.balance); ount.Deposit(decimal.Parse(state.ToString())); Console.WriteLine("Deposit: new balance = {0:C}", ount.balance); } } }

queueuserworkitem是异步的还是同步的

串行通信是指 使用一条数据线，将数据一位一位地依次传输，每一位数据占据一个固定的时间长度。

其只需要少数几条线就可以在系统间交换信息，特别适用于计算机与计算机、计算机与外设之间的远距离通信。

在计算机和终端之间的数据传输通常是靠电缆或信道上的电流或电压变化实现的。

如果一组数据的各数据位在多条线上同时被传输，这种传输方式称为并行通信。

同步通信与异步通信区别： 1.同步通信要求接收端时钟频率和发送端时钟频率一致，发送端发送连续的比特流；异步通信时不要求接收端时钟和发送端时钟同步，发送端发送完一个字节后，可经过任意长的时间间隔再发送下一个字节。

2.同步通信效率高；异步通信效率较低。

3.同步通信较复杂，双方时钟的允许误差较小；异步通信简单，双方时钟可允许一定误差。

4.同步通信可用于点对多点；异步通信只适用于点对点。

如何创建线程

方式1：继承Thread类 步骤: 1):定义一个类A继承于Java.lang.Thread类. 2):在A类中覆盖Thread类中的run方法. 3):我们在run方法中编写需要执行的操作：run方法里的代码,线程执行体. 4):在main方法(线程)中,创建线程对象,并启动线程. (1)创建线程类