C#中编写多线程应用程序

以前在使用VB来实现多线程的时候，发现有一定的难度。虽然也有这样那样的方法，但都不尽人意，但在C#中，要编写多线程应用程序却相当的简单。这篇文章将作简要的介绍，以起到抛砖引玉的作用！

.NET将关于多线程的功能定义在System.Threading名字空间中。因此，要使用多线程，必须先声明引用此名字空间（using System.Threading;）。

即使你没有编写多线程应用程序的经验，也可能听说过“启动线程”“杀死线程”这些词，其实除了这两个外，涉及多线程方面的还有诸如“暂停线程”“优先级”“挂起线程”“恢复线程”等等。下面将一个一个的解释。

a.启动线程

顾名思义，“启动线程”就是新建并启动一个线程的意思，如下代码可实现：

Thread thread1 = new Thread(new ThreadStart( Count));

其中的 Count 是将要被新线程执行的函数。

b.杀死线程

“杀死线程”就是将一线程斩草除根，为了不白费力气，在杀死一个线程前最好先判断它是否还活着（通过 IsAlive 属性），然后就可以调用 Abort 方法来杀死此线程。

c.暂停线程

它的意思就是让一个正在运行的线程休眠一段时间。如 thread.Sleep(1000); 就是让线程休眠1秒钟。

d.优先级

这个用不着解释了。Thread类中有一个ThreadPriority属性，它用来设置优先级，但不能保证操作系统会接受该优先级。一个线程的优先级可分为5种：Normal, AboveNormal, BelowNormal, Highest, Lowest。具体实现例子如下:

thread.Priority = ThreadPriority.Highest;

e.挂起线程

Thread类的Suspend方法用来挂起线程，知道调用Resume，此线程才可以继续执行。如果线程已经挂起，那就不会起作用。

if (thread.ThreadState = ThreadState.Running)

{

thread.Suspend();

}

f.恢复线程

用来恢复已经挂起的线程，以让它继续执行，如果线程没挂起，也不会起作用。

if (thread.ThreadState = ThreadState.Suspended)

{

thread.Resume();

}

下面将列出一个例子，以说明简单的线程处理功能。此例子来自于帮助文档。

using System;

using System.Threading;

// Simple threading scenario: Start a static method running

// on a second thread.

public class ThreadExample {

// The ThreadProc method is called when the thread starts.

// It loops ten times, writing to the console and yielding

// the rest of its time slice each time, and then ends.

public static void ThreadProc() {

for (int i = 0; i < 10; i++) {

Console.WriteLine("ThreadProc: {0}", i);

// Yield the rest of the time slice.

Thread.Sleep(0);

}

}

public static void Main() {

Console.WriteLine("Main thread: Start a second thread.");

// The constructor for the Thread class requires a ThreadStart

// delegate that represents the method to be executed on the

// thread. C# simplifies the creation of this delegate.

Thread t = new Thread(new ThreadStart(ThreadProc));

// Start ThreadProc. On a uniprocessor, the thread does not get

// any processor time until the main thread yields. Uncomment

// the Thread.Sleep that follows t.Start() to see the difference.

t.Start();

//Thread.Sleep(0);

for (int i = 0; i < 4; i++) {

Console.WriteLine("Main thread: Do some work.");

Thread.Sleep(0);

}

Console.WriteLine("Main thread: Call Join(), to wait until ThreadProc ends.");

t.Join();

Console.WriteLine("Main thread: ThreadProc.Join has returned. Press Enter to end program.");

Console.ReadLine();

}

}

此代码产生的输出类似如下内容：

Main thread: Start a second thread.

Main thread: Do some work.

ThreadProc: 0

Main thread: Do some work.

ThreadProc: 1

Main thread: Do some work.

ThreadProc: 2

Main thread: Do some work.

ThreadProc: 3

Main thread: Call Join(), to wait until ThreadProc ends.

ThreadProc: 4

ThreadProc: 5

ThreadProc: 6

ThreadProc: 7

ThreadProc: 8

ThreadProc: 9

Main thread: ThreadProc.Join has returned. Press Enter to end program

c#中使用多线程（图） 选择自 iuhxq 的 Blog

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using System.Threading;

namespace student

{

/// <summary>

/// Form1 的摘要说明。

/// </summary>

public class Form1 : System.Windows.Forms.Form

{

private System.Windows.Forms.Button button1;

private System.Windows.Forms.Button button2;

private System.Windows.Forms.Button button3;

ArrayList threads = new ArrayList();

private System.Windows.Forms.ListView listView1;

private System.Windows.Forms.ColumnHeader columnHeader1;

private System.Windows.Forms.ColumnHeader columnHeader2;

/// <summary>

/// 必需的设计器变量。

/// </summary>

private System.ComponentModel.Container components = null;

public Form1()

{

//

// Windows 窗体设计器支持所必需的

//

InitializeComponent();

//

// TODO: 在 InitializeComponent 调用后添加任何构造函数代码

//

}

/// <summary>

/// 清理所有正在使用的资源。

/// </summary>

protected override void Dispose( bool disposing )

{

if( disposing )

{

if (components != null)

{

components.Dispose();

}

}

base.Dispose( disposing );

}

#region Windows 窗体设计器生成的代码

/// <summary>

/// 设计器支持所需的方法 - 不要使用代码编辑器修改

/// 此方法的内容。

/// </summary>

private void InitializeComponent()

{

this.button1 = new System.Windows.Forms.Button();

this.button2 = new System.Windows.Forms.Button();

this.button3 = new System.Windows.Forms.Button();

this.listView1 = new System.Windows.Forms.ListView();

this.columnHeader1 = new System.Windows.Forms.ColumnHeader();

this.columnHeader2 = new System.Windows.Forms.ColumnHeader();

this.SuspendLayout();

//

// button1

//

this.button1.Location = new System.Drawing.Point(24, 216);

this.button1.Name = "button1";

this.button1.TabIndex = 1;

this.button1.Text = "Add";

this.button1.Click += new System.EventHandler(this.button1_Click);

//

// button2

//

this.button2.Location = new System.Drawing.Point(104, 216);

this.button2.Name = "button2";

this.button2.TabIndex = 2;

this.button2.Text = "Del";

this.button2.Click += new System.EventHandler(this.button2_Click);

//

// button3

//

this.button3.Location = new System.Drawing.Point(184, 216);

this.button3.Name = "button3";

this.button3.TabIndex = 3;

this.button3.Text = "DelAll";

this.button3.Click += new System.EventHandler(this.button3_Click);

//

// listView1

//

this.listView1.Columns.AddRange(new System.Windows.Forms.ColumnHeader[] {

this.columnHeader1,

this.columnHeader2});

this.listView1.FullRowSelect = true;

this.listView1.GridLines = true;

this.listView1.Location = new System.Drawing.Point(0, 0);

this.listView1.Name = "listView1";

this.listView1.Size = new System.Drawing.Size(288, 208);

this.listView1.TabIndex = 5;

this.listView1.View = System.Windows.Forms.View.Details;

//

// columnHeader1

//

this.columnHeader1.Text = "线程编号";

this.columnHeader1.Width = 81;

//

// columnHeader2

//

this.columnHeader2.Text = "value";

this.columnHeader2.Width = 180;

//

// Form1

//

this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);

this.ClientSize = new System.Drawing.Size(292, 266);

this.Controls.Add(this.listView1);

this.Controls.Add(this.button3);

this.Controls.Add(this.button2);

this.Controls.Add(this.button1);

this.Name = "Form1";

this.Text = "Form1";

this.Load += new System.EventHandler(this.Form1_Load);

this.ResumeLayout(false);

}

#endregion

/// <summary>

/// 应用程序的主入口点。

/// </summary>

[STAThread]

static void Main()

{

Application.Run(new Form1());

}

private void Form1_Load(object sender, System.EventArgs e)

{

}

private void button1_Click(object sender, System.EventArgs e)

{

Add();

}

private void button2_Click(object sender, System.EventArgs e)

{

Del();

}

private void button3_Click(object sender, System.EventArgs e)

{

while(threads.Count>0)

{

Thread t1 = (Thread)threads[0];

if(t1.IsAlive)

{

t1.Abort();

}

threads.RemoveAt(0);

lock(listView1)

{

listView1.Items.RemoveAt(0);

}

}

}

private void Add()

{

int count = threads.Count;

if(count<10)

{

Thread t = new Thread(new ThreadStart(Process));

t.Start();

threads.Add(t);

lock(listView1)

{

listView1.Items.Insert(count, new ListViewItem(new string[]{count.ToString(),"0"}));

}

}

}

private void Del()

{

int count = threads.Count;

if(count>0)

{

Thread t1 = (Thread)threads[count-1];

if(t1.IsAlive)

{

t1.Abort();

}

threads.RemoveAt(count-1);

lock(listView1)

{

listView1.Items.RemoveAt(count-1);

}

}

}

private void Process()

{

int i = 1;

while(true)

{

i++;

int j = threads.IndexOf(Thread.CurrentThread);

lock(listView1)

{

listView1.Items[j].SubItems[1].Text = i.ToString();

}

Thread.Sleep(0);

}

}

}

}

}

}

}