C#网络编程一：C#网络编程常用特性

Posted 2020-08-24 .NET开发菜鸟

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：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Threading.Tasks;
 9 using System.Windows.Forms;
10 
11 namespace DelegateDemo
12 {
13     public partial class FrmMain : Form
14     {
15         public FrmMain()
16         {
17             InitializeComponent();
18         }
19 
20         //1、定义委托
21         private delegate void WriteToTextBox(string strTxt);
22         //2、声明委托
23         private WriteToTextBox writeToTextBox;
24 
25         /// <summary>
26         /// 提交
27         /// </summary>
28         /// <param name="sender"></param>
29         /// <param name="e"></param>
30         private void btn_OK_Click(object sender, EventArgs e)
31         {
32             if (chbOne.Checked)
33             {
34                 gbJobOne.Text = "运行中......";
35                 gbJobOne.Refresh();
36                 txtJobOne.Clear();
37                 //3、实例化委托
38                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
39                 //4、将委托作为方法的参数进行传递
40                 WriteText(writeToTextBox);
41                 gbJobOne.Text = "任务1完成";
42             }
43             if (chbTwo.Checked)
44             {
45 
46                 gbJobTwo.Text = "运行中......";
47                 gbJobTwo.Refresh();
48                 txtJobTwo.Clear();
49                 //3、实例化委托
50                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
51                 //4、将委托作为方法的参数进行传递
52                 WriteText(writeToTextBox);
53                 gbJobTwo.Text = "任务2完成";
54             }
55         }
56 
57 
58         private void WriteText(WriteToTextBox writeMethod)
59         {
60             string strData = this.txt_Input.Text;
61             writeMethod(strData);
62         }
63         private void WriteTextBox1(string strTxt)
64         {
65             this.txtJobOne.Text = strTxt;
66         }
67 
68         private void WriteTextBox2(string strTxt)
69         {
70             this.txtJobTwo.Text = strTxt;
71         }
72 
73         /// <summary>
74         /// 窗体加载事件
75         /// </summary>
76         /// <param name="sender"></param>
77         /// <param name="e"></param>
78         private void FrmMain_Load(object sender, EventArgs e)
79         {
80             //设置文本框获取焦点
81             this.ActiveControl = this.txt_Input;
82             //this.txt_Input.Focus();
83         }
84     }
85 }

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：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.ComponentModel;
  4 using System.Data;
  5 using System.Drawing;
  6 using System.Linq;
  7 using System.Text;
  8 using System.Threading.Tasks;
  9 using System.Windows.Forms;
 10 using System.Threading;//引入多线程的命名空间
 11 
 12 namespace DelegateDemo
 13 {
 14     public partial class FrmMain : Form
 15     {
 16         public FrmMain()
 17         {
 18             InitializeComponent();
 19         }
 20 
 21         //1、定义委托
 22         private delegate void WriteToTextBox(string strTxt);
 23         //2、声明委托
 24         private WriteToTextBox writeToTextBox;
 25 
 26         /// <summary>
 27         /// 提交
 28         /// </summary>
 29         /// <param name="sender"></param>
 30         /// <param name="e"></param>
 31         private void btn_OK_Click(object sender, EventArgs e)
 32         {
 33            //创建线程1
 34             Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
 35             //启动线程1
 36             thread1.Start();
 37 
 38             //创建线程2
 39             Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
 40             //启动线程2
 41             thread2.Start();
 42            
 43         }
 44 
 45 
 46         private void ExecuteTsk1()
 47         {
 48             if (chbOne.Checked)
 49             {
 50                 gbJobOne.Text = "运行中......";
 51                 gbJobOne.Refresh();
 52                 txtJobOne.Clear();
 53                 //3、实例化委托
 54                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
 55                 //4、将委托作为方法的参数进行传递
 56                 WriteText(writeToTextBox);
 57                 gbJobOne.Text = "任务1完成";
 58             }
 59         }
 60 
 61         private void ExecuteTsk2()
 62         {
 63             if (chbTwo.Checked)
 64             {
 65 
 66                 gbJobTwo.Text = "运行中......";
 67                 gbJobTwo.Refresh();
 68                 txtJobTwo.Clear();
 69                 //3、实例化委托
 70                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
 71                 //4、将委托作为方法的参数进行传递
 72                 WriteText(writeToTextBox);
 73                 gbJobTwo.Text = "任务2完成";
 74             }
 75         }
 76 
 77 
 78         private void WriteText(WriteToTextBox writeMethod)
 79         {
 80             string strData = this.txt_Input.Text;
 81             writeMethod(strData);
 82         }
 83         private void WriteTextBox1(string strTxt)
 84         {
 85             this.txtJobOne.Text = strTxt;
 86         }
 87 
 88         private void WriteTextBox2(string strTxt)
 89         {
 90             this.txtJobTwo.Text = strTxt;
 91         }
 92 
 93         /// <summary>
 94         /// 窗体加载事件
 95         /// </summary>
 96         /// <param name="sender"></param>
 97         /// <param name="e"></param>
 98         private void FrmMain_Load(object sender, EventArgs e)
 99         {
100             //设置文本框获取焦点
101             this.ActiveControl = this.txt_Input;
102             //允许跨线程调用
103             Control.CheckForIllegalCrossThreadCalls = false;
104         }
105     }
106 }

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：

 

  1 using System;
  2 using System.Collections.Generic;
  3 using System.ComponentModel;
  4 using System.Data;
  5 using System.Drawing;
  6 using System.Linq;
  7 using System.Text;
  8 using System.Threading.Tasks;
  9 using System.Windows.Forms;
 10 using System.Threading;//引入多线程的命名空间
 11 
 12 namespace DelegateDemo
 13 {
 14     public partial class FrmMain : Form
 15     {
 16         public FrmMain()
 17         {
 18             InitializeComponent();
 19         }
 20 
 21         //1、定义委托
 22         private delegate void WriteToTextBox(string strTxt);
 23         //2、声明委托
 24         private WriteToTextBox writeToTextBox;
 25 
 26         //定义并声明操作文本区1的回调
 27         private delegate void WriteTxtJobOneCallBack(string strValue);
 28         WriteTxtJobOneCallBack writeTxtJobOneCallBack;
 29 
 30         //定义并声明操作文本区2的回调
 31         private delegate void WriteTxtJobTwoCallBack(string strValue);
 32         WriteTxtJobOneCallBack writeTxtJobTwoCallBack;
 33 
 34         //定义并声明操作"任务1"分组框的回调
 35         private delegate void ShowGroupOneCallBack(string strValue);
 36         ShowGroupOneCallBack showGroupOneCallBack;
 37 
 38         //定义并声明操作"任务2"分组框的回调
 39         private delegate void ShowGroupTwoCallBack(string strValue);
 40         ShowGroupOneCallBack showGroupTwoCallBack;
 41 
 42        
 43         
 44         /// <summary>
 45         /// 提交
 46         /// </summary>
 47         /// <param name="sender"></param>
 48         /// <param name="e"></param>
 49         private void btn_OK_Click(object sender, EventArgs e)
 50         {
 51            //创建线程1
 52             Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
 53             //启动线程1
 54             thread1.Start();
 55 
 56             //创建线程2
 57             Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
 58             //启动线程2
 59             thread2.Start();
 60            
 61         }
 62 
 63 
 64         private void ExecuteTsk1()
 65         {
 66             if (chbOne.Checked)
 67             {
 68                 //3、实例化委托
 69                 writeToTextBox = new WriteToTextBox(WriteTextBox1);
 70                 //4、将委托作为方法的参数进行传递
 71                 WriteText(writeToTextBox);
 72                 //使用回调
 73                 this.gbJobOne.Invoke(showGroupOneCallBack, "任务1");
 74             }
 75         }
 76 
 77         private void ExecuteTsk2()
 78         {
 79             if (chbTwo.Checked)
 80             {
 81                 //3、实例化委托
 82                 writeToTextBox = new WriteToTextBox(WriteTextBox2);
 83                 //4、将委托作为方法的参数进行传递
 84                 WriteText(writeToTextBox);
 85                 //使用回调
 86                 this.gbJobTwo.Invoke(showGroupTwoCallBack, "任务2");
 87             }
 88         }
 89 
 90         /// <summary>
 91         /// 执行自定义委托
 92         /// </summary>
 93         /// <param name="writeMethod"></param>
 94         private void WriteText(WriteToTextBox writeMethod)
 95         {
 96             string strData = this.txt_Input.Text;
 97             writeMethod(strData);
 98         }
 99 
100         /// <summary>
101         /// 给文本区1赋值
102         /// </summary>
103         /// <param name="strTxt"></param>
104         private void WriteTextBox1(string strTxt)
105         {
106             //使用回调
107             this.txtJobOne.Invoke(writeTxtJobOneCallBack, strTxt);
108         }
109 
110         /// <summary>
111         /// 给文本区2赋值
112         /// </summary>
113         /// <param name="strTxt"></param>
114         private void WriteTextBox2(string strTxt)
115         {
116             //使用回调
117             this.txtJobTwo.Invoke(writeTxtJobTwoCallBack, strTxt);
118         }
119 
120         /// <summary>
121         /// 窗体加载事件
122         /// </summary>
123         /// <param name="sender"></param>
124         /// <param name="e"></param>
125         private void FrmMain_Load(object sender, EventArgs e)
126         {
127             //设置文本框获取焦点
128             this.ActiveControl = this.txt_Input;
129             
130             //实例化回调
131             writeTxtJobOneCallBack = new WriteTxtJobOneCallBack(WriteToTextJobOne);
132             writeTxtJobTwoCallBack = new WriteTxtJobOneCallBack(WriteToTextJobTwo);
133             showGroupOneCallBack = new ShowGroupOneCallBack(ShowGroupOne);
134             showGroupTwoCallBack = new ShowGroupOneCallBack(ShowGroupTwo);
135 
136         }
137 
138         /// <summary>
139         /// 操作文本区1的回调要执行的方法
140         /// </summary>
141         /// <param name="strValue"></param>
142         private void WriteToTextJobOne(string strValue)
143         {
144             this.txtJobOne.Text = strValue;
145         }
146 
147         /// <summary>
148         /// 操作文本区2的回调要执行的方法
149         /// </summary>
150         /// <param name="strValue"></param>
151         private void WriteToTextJobTwo(string strValue)
152         {
153             this.txtJobTwo.Text = strValue;
154         }
155 
156         /// <summary>
157         /// 操作"任务1"分组框的回调要执行的方法
158         /// </summary>
159         /// <param name="strValue"></param>
160         private void ShowGroupOne(string strValue)
161         {
162             this.gbJobOne.Text = strValue;
163         }
164 
165         /// <summary>
166         /// 操作"任务2"分组框的回调要执行的方法
167         /// </summary>
168         /// <param name="strValue"></param>
169         private void ShowGroupTwo(string strValue)
170         {
171             this.gbJobTwo.Text = strValue;
172         }
173     }
174 }