C#网络编程一：C#网络编程常用特性

特性一：委托

委托是C#语言中特有的概念，相当于C/C++中的函数指针，与C/C++中函数指针的不同之处是：委托是面向对象的、类型安全的和保险的，是引用类型。因此，对委托的使用要

“先定义、后声明，接着实例化、然后作为参数传递给方法，最后才能使用”。

1、定义委托使用关键字delegate:

delegate  void SomeDelegate(type1 para1,......typen paran);

2、声明委托：

SomeDelegate  d;

3、实例化委托：

d=new SomeDelegate(obj.InstanceMethod);

其中obj是对象，InstanceMethod是它的实例方法。

4、作为参数传递给方法

someMethod(d);

5、最后在此方法的实现代码中使用委托

private  void  someMethod(SomeDelegate  someDelegate)

{

.....

//使用委托

someDelegate(arg1,arg2,....,argn);

......

}

通过委托SomeDelegate实现对方法InstanceMethod的调用，调用还必须有一个前提条件：方法InstanceMethod有参数且和定义SomeDelegate的参数一致，并且返回类型相同（本例中为void）。方法InstanceMethod的定义：

private  void  InstanceMethod(type1 para1,type2 para2,......,typen paran)

{

//方法体

.....

}

委托的实例化中的参数既可以是实例方法，也可以是静态方法。

使用委托实现“文字抄写员”的小程序，界面如下：

在下方文本框中编辑文字，勾选“书写到”组框中的“文本区1”和（或）“文本区2”复选框后单击“提交”按钮，程序会自动将文本框中的文字“抄写”到对应的用户勾选的文本区中去。

代码实现如下：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;

 namespace DelegateDemo
 {
     public partial class FrmMain : Form
     {
         public FrmMain()
         {
             InitializeComponent();
         }

         //1、定义委托
         private delegate void WriteToTextBox(string strTxt);
         //2、声明委托
         private WriteToTextBox writeToTextBox;

         /// <summary>
         /// 提交
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btn_OK_Click(object sender, EventArgs e)
         {
             if (chbOne.Checked)
             {
                 gbJobOne.Text = "运行中......";
                 gbJobOne.Refresh();
                 txtJobOne.Clear();
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 gbJobOne.Text = "任务1完成";
             }
             if (chbTwo.Checked)
             {

                 gbJobTwo.Text = "运行中......";
                 gbJobTwo.Refresh();
                 txtJobTwo.Clear();
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 gbJobTwo.Text = "任务2完成";
             }
         }

         private void WriteText(WriteToTextBox writeMethod)
         {
             string strData = this.txt_Input.Text;
             writeMethod(strData);
         }
         private void WriteTextBox1(string strTxt)
         {
             this.txtJobOne.Text = strTxt;
         }

         private void WriteTextBox2(string strTxt)
         {
             this.txtJobTwo.Text = strTxt;
         }

         /// <summary>
         /// 窗体加载事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void FrmMain_Load(object sender, EventArgs e)
         {
             //设置文本框获取焦点
             this.ActiveControl = this.txt_Input;
             //this.txt_Input.Focus();
         }
     }
 }

特性2：多线程

多线程的具体介绍请参考博文：http://www.cnblogs.com/dotnet261010/p/6159984.html

使用多线程实现上一节的程序，代码如下：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using System.Threading;//引入多线程的命名空间

 namespace DelegateDemo
 {
     public partial class FrmMain : Form
     {
         public FrmMain()
         {
             InitializeComponent();
         }

         //1、定义委托
         private delegate void WriteToTextBox(string strTxt);
         //2、声明委托
         private WriteToTextBox writeToTextBox;

         /// <summary>
         /// 提交
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btn_OK_Click(object sender, EventArgs e)
         {
            //创建线程1
             Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
             //启动线程1
             thread1.Start();

             //创建线程2
             Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
             //启动线程2
             thread2.Start();

         }

         private void ExecuteTsk1()
         {
             if (chbOne.Checked)
             {
                 gbJobOne.Text = "运行中......";
                 gbJobOne.Refresh();
                 txtJobOne.Clear();
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 gbJobOne.Text = "任务1完成";
             }
         }

         private void ExecuteTsk2()
         {
             if (chbTwo.Checked)
             {

                 gbJobTwo.Text = "运行中......";
                 gbJobTwo.Refresh();
                 txtJobTwo.Clear();
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 gbJobTwo.Text = "任务2完成";
             }
         }

         private void WriteText(WriteToTextBox writeMethod)
         {
             string strData = this.txt_Input.Text;
             writeMethod(strData);
         }
         private void WriteTextBox1(string strTxt)
         {
             this.txtJobOne.Text = strTxt;
         }

         private void WriteTextBox2(string strTxt)
         {
             this.txtJobTwo.Text = strTxt;
         }

         /// <summary>
         /// 窗体加载事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void FrmMain_Load(object sender, EventArgs e)
         {
             //设置文本框获取焦点
             this.ActiveControl = this.txt_Input;
             //允许跨线程调用
             Control.CheckForIllegalCrossThreadCalls = false;
         }
     }
 }

特性3：C#方法回调

C#回调的具体介绍请参照博文：http://www.cnblogs.com/dotnet261010/p/6159984.html

使用委托、多线程和C#的方法回调机制实现上一节的程序，代码如下：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using System.Threading;//引入多线程的命名空间

 namespace DelegateDemo
 {
     public partial class FrmMain : Form
     {
         public FrmMain()
         {
             InitializeComponent();
         }

         //1、定义委托
         private delegate void WriteToTextBox(string strTxt);
         //2、声明委托
         private WriteToTextBox writeToTextBox;

         //定义并声明操作文本区1的回调
         private delegate void WriteTxtJobOneCallBack(string strValue);
         WriteTxtJobOneCallBack writeTxtJobOneCallBack;

         //定义并声明操作文本区2的回调
         private delegate void WriteTxtJobTwoCallBack(string strValue);
         WriteTxtJobOneCallBack writeTxtJobTwoCallBack;

         //定义并声明操作"任务1"分组框的回调
         private delegate void ShowGroupOneCallBack(string strValue);
         ShowGroupOneCallBack showGroupOneCallBack;

         //定义并声明操作"任务2"分组框的回调
         private delegate void ShowGroupTwoCallBack(string strValue);
         ShowGroupOneCallBack showGroupTwoCallBack;

         /// <summary>
         /// 提交
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btn_OK_Click(object sender, EventArgs e)
         {
            //创建线程1
             Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
             //启动线程1
             thread1.Start();

             //创建线程2
             Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
             //启动线程2
             thread2.Start();

         }

         private void ExecuteTsk1()
         {
             if (chbOne.Checked)
             {
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 //使用回调
                 this.gbJobOne.Invoke(showGroupOneCallBack, "任务1");
             }
         }

         private void ExecuteTsk2()
         {
             if (chbTwo.Checked)
             {
                 //3、实例化委托
                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
                 //4、将委托作为方法的参数进行传递
                 WriteText(writeToTextBox);
                 //使用回调
                 this.gbJobTwo.Invoke(showGroupTwoCallBack, "任务2");
             }
         }

         /// <summary>
         /// 执行自定义委托
         /// </summary>
         /// <param name="writeMethod"></param>
         private void WriteText(WriteToTextBox writeMethod)
         {
             string strData = this.txt_Input.Text;
             writeMethod(strData);
         }

         /// <summary>
         /// 给文本区1赋值
         /// </summary>
         /// <param name="strTxt"></param>
         private void WriteTextBox1(string strTxt)
         {
             //使用回调
             this.txtJobOne.Invoke(writeTxtJobOneCallBack, strTxt);
         }

         /// <summary>
         /// 给文本区2赋值
         /// </summary>
         /// <param name="strTxt"></param>
         private void WriteTextBox2(string strTxt)
         {
             //使用回调
             this.txtJobTwo.Invoke(writeTxtJobTwoCallBack, strTxt);
         }

         /// <summary>
         /// 窗体加载事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void FrmMain_Load(object sender, EventArgs e)
         {
             //设置文本框获取焦点
             this.ActiveControl = this.txt_Input;

             //实例化回调
             writeTxtJobOneCallBack = new WriteTxtJobOneCallBack(WriteToTextJobOne);
             writeTxtJobTwoCallBack = new WriteTxtJobOneCallBack(WriteToTextJobTwo);
             showGroupOneCallBack = new ShowGroupOneCallBack(ShowGroupOne);
             showGroupTwoCallBack = new ShowGroupOneCallBack(ShowGroupTwo);

         }

         /// <summary>
         /// 操作文本区1的回调要执行的方法
         /// </summary>
         /// <param name="strValue"></param>
         private void WriteToTextJobOne(string strValue)
         {
             this.txtJobOne.Text = strValue;
         }

         /// <summary>
         /// 操作文本区2的回调要执行的方法
         /// </summary>
         /// <param name="strValue"></param>
         private void WriteToTextJobTwo(string strValue)
         {
             this.txtJobTwo.Text = strValue;
         }

         /// <summary>
         /// 操作"任务1"分组框的回调要执行的方法
         /// </summary>
         /// <param name="strValue"></param>
         private void ShowGroupOne(string strValue)
         {
             this.gbJobOne.Text = strValue;
         }

         /// <summary>
         /// 操作"任务2"分组框的回调要执行的方法
         /// </summary>
         /// <param name="strValue"></param>
         private void ShowGroupTwo(string strValue)
         {
             this.gbJobTwo.Text = strValue;
         }
     }
 }