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C#網(wǎng)絡(luò)編程中常用特性介紹_C#教程

作者：.NET開(kāi)發(fā)菜鳥(niǎo) ? 更新時(shí)間： 2022-04-28 編程語(yǔ)言

特性一：委托

委托是C#語(yǔ)言中特有的概念，相當(dāng)于C/C++中的函數(shù)指針，與C/C++中函數(shù)指針的不同之處是：委托是面向?qū)ο蟮摹㈩愋桶踩暮捅ｋU(xiǎn)的，是引用類型。因此，對(duì)委托的使用要

“先定義、后聲明，接著實(shí)例化、然后作為參數(shù)傳遞給方法，最后才能使用”。

1、定義委托使用關(guān)鍵字delegate:

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

2、聲明委托：

SomeDelegate? d;

3、實(shí)例化委托：

d=new SomeDelegate(obj.InstanceMethod);

其中obj是對(duì)象，InstanceMethod是它的實(shí)例方法。

4、作為參數(shù)傳遞給方法

someMethod(d);

5、最后在此方法的實(shí)現(xiàn)代碼中使用委托

private? void? someMethod(SomeDelegate? someDelegate)
{
?? .....
?? //使用委托
? someDelegate(arg1,arg2,....,argn);
? ......?
}

通過(guò)委托SomeDelegate實(shí)現(xiàn)對(duì)方法InstanceMethod的調(diào)用，調(diào)用還必須有一個(gè)前提條件：方法InstanceMethod有參數(shù)且和定義SomeDelegate的參數(shù)一致，并且返回類型相同（本例中為void）。方法InstanceMethod的定義：

private? void? InstanceMethod(type1 para1,type2 para2,......,typen paran)
{
?? //方法體
? .....
}

委托的實(shí)例化中的參數(shù)既可以是實(shí)例方法，也可以是靜態(tài)方法。

使用委托實(shí)現(xiàn)“文字抄寫(xiě)員”的小程序，界面如下：

在下方文本框中編輯文字，勾選“書(shū)寫(xiě)到”組框中的“文本區(qū)1”和（或）“文本區(qū)2”復(fù)選框后單擊“提交”按鈕，程序會(huì)自動(dòng)將文本框中的文字“抄寫(xiě)”到對(duì)應(yīng)的用戶勾選的文本區(qū)中去。

代碼實(shí)現(xiàn)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、定義委托
        private delegate void WriteToTextBox(string strTxt);
        //2、聲明委托
        private WriteToTextBox writeToTextBox;

        /// 
        /// 提交
        /// 
        /// 
        /// 
        private void btn_OK_Click(object sender, EventArgs e)
        {
            if (chbOne.Checked)
            {
                gbJobOne.Text = "運(yùn)行中......";
                gbJobOne.Refresh();
                txtJobOne.Clear();
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox1);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                gbJobOne.Text = "任務(wù)1完成";
            }
            if (chbTwo.Checked)
            {

                gbJobTwo.Text = "運(yùn)行中......";
                gbJobTwo.Refresh();
                txtJobTwo.Clear();
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox2);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                gbJobTwo.Text = "任務(wù)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;
        }

        /// 
        /// 窗體加載事件
        /// 
        /// 
        /// 
        private void FrmMain_Load(object sender, EventArgs e)
        {
            //設(shè)置文本框獲取焦點(diǎn)
            this.ActiveControl = this.txt_Input;
            //this.txt_Input.Focus();
        }
    }
}

特性2：多線程

多線程的具體介紹請(qǐng)參考博文：https://www.jb51.net/article/238731.htm

使用多線程實(shí)現(xiàn)上一節(jié)的程序，代碼如下：

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;//引入多線程的命名空間

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

        //1、定義委托
        private delegate void WriteToTextBox(string strTxt);
        //2、聲明委托
        private WriteToTextBox writeToTextBox;

        /// 
        /// 提交
        /// 
        /// 
        /// 
        private void btn_OK_Click(object sender, EventArgs e)
        {
           //創(chuàng)建線程1
            Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
            //啟動(dòng)線程1
            thread1.Start();

            //創(chuàng)建線程2
            Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
            //啟動(dòng)線程2
            thread2.Start();

        }


        private void ExecuteTsk1()
        {
            if (chbOne.Checked)
            {
                gbJobOne.Text = "運(yùn)行中......";
                gbJobOne.Refresh();
                txtJobOne.Clear();
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox1);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                gbJobOne.Text = "任務(wù)1完成";
            }
        }

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

                gbJobTwo.Text = "運(yùn)行中......";
                gbJobTwo.Refresh();
                txtJobTwo.Clear();
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox2);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                gbJobTwo.Text = "任務(wù)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;
        }

        /// 
        /// 窗體加載事件
        /// 
        /// 
        /// 
        private void FrmMain_Load(object sender, EventArgs e)
        {
            //設(shè)置文本框獲取焦點(diǎn)
            this.ActiveControl = this.txt_Input;
            //允許跨線程調(diào)用
            Control.CheckForIllegalCrossThreadCalls = false;
        }
    }
}

特性3：C#方法回調(diào)

C#回調(diào)的具體介紹請(qǐng)參照博文：https://www.jb51.net/article/238731.htm#_label3

使用委托、多線程和C#的方法回調(diào)機(jī)制實(shí)現(xiàn)上一節(jié)的程序，代碼如下：

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;//引入多線程的命名空間

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

        //1、定義委托
        private delegate void WriteToTextBox(string strTxt);
        //2、聲明委托
        private WriteToTextBox writeToTextBox;

        //定義并聲明操作文本區(qū)1的回調(diào)
        private delegate void WriteTxtJobOneCallBack(string strValue);
        WriteTxtJobOneCallBack writeTxtJobOneCallBack;

        //定義并聲明操作文本區(qū)2的回調(diào)
        private delegate void WriteTxtJobTwoCallBack(string strValue);
        WriteTxtJobOneCallBack writeTxtJobTwoCallBack;

        //定義并聲明操作"任務(wù)1"分組框的回調(diào)
        private delegate void ShowGroupOneCallBack(string strValue);
        ShowGroupOneCallBack showGroupOneCallBack;

        //定義并聲明操作"任務(wù)2"分組框的回調(diào)
        private delegate void ShowGroupTwoCallBack(string strValue);
        ShowGroupOneCallBack showGroupTwoCallBack;



        /// 
        /// 提交
        /// 
        /// 
        /// 
        private void btn_OK_Click(object sender, EventArgs e)
        {
           //創(chuàng)建線程1
            Thread thread1 = new Thread(new ThreadStart(ExecuteTsk1));
            //啟動(dòng)線程1
            thread1.Start();

            //創(chuàng)建線程2
            Thread thread2 = new Thread(new ThreadStart(ExecuteTsk2));
            //啟動(dòng)線程2
            thread2.Start();

        }


        private void ExecuteTsk1()
        {
            if (chbOne.Checked)
            {
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox1);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                //使用回調(diào)
                this.gbJobOne.Invoke(showGroupOneCallBack, "任務(wù)1");
            }
        }

        private void ExecuteTsk2()
        {
            if (chbTwo.Checked)
            {
                //3、實(shí)例化委托
                writeToTextBox = new WriteToTextBox(WriteTextBox2);
                //4、將委托作為方法的參數(shù)進(jìn)行傳遞
                WriteText(writeToTextBox);
                //使用回調(diào)
                this.gbJobTwo.Invoke(showGroupTwoCallBack, "任務(wù)2");
            }
        }

        /// 
        /// 執(zhí)行自定義委托
        /// 
        /// 
        private void WriteText(WriteToTextBox writeMethod)
        {
            string strData = this.txt_Input.Text;
            writeMethod(strData);
        }

        /// 
        /// 給文本區(qū)1賦值
        /// 
        /// 
        private void WriteTextBox1(string strTxt)
        {
            //使用回調(diào)
            this.txtJobOne.Invoke(writeTxtJobOneCallBack, strTxt);
        }

        /// 
        /// 給文本區(qū)2賦值
        /// 
        /// 
        private void WriteTextBox2(string strTxt)
        {
            //使用回調(diào)
            this.txtJobTwo.Invoke(writeTxtJobTwoCallBack, strTxt);
        }

        /// 
        /// 窗體加載事件
        /// 
        /// 
        /// 
        private void FrmMain_Load(object sender, EventArgs e)
        {
            //設(shè)置文本框獲取焦點(diǎn)
            this.ActiveControl = this.txt_Input;

            //實(shí)例化回調(diào)
            writeTxtJobOneCallBack = new WriteTxtJobOneCallBack(WriteToTextJobOne);
            writeTxtJobTwoCallBack = new WriteTxtJobOneCallBack(WriteToTextJobTwo);
            showGroupOneCallBack = new ShowGroupOneCallBack(ShowGroupOne);
            showGroupTwoCallBack = new ShowGroupOneCallBack(ShowGroupTwo);

        }

        /// 
        /// 操作文本區(qū)1的回調(diào)要執(zhí)行的方法
        /// 
        /// 
        private void WriteToTextJobOne(string strValue)
        {
            this.txtJobOne.Text = strValue;
        }

        /// 
        /// 操作文本區(qū)2的回調(diào)要執(zhí)行的方法
        /// 
        /// 
        private void WriteToTextJobTwo(string strValue)
        {
            this.txtJobTwo.Text = strValue;
        }

        /// 
        /// 操作"任務(wù)1"分組框的回調(diào)要執(zhí)行的方法
        /// 
        /// 
        private void ShowGroupOne(string strValue)
        {
            this.gbJobOne.Text = strValue;
        }

        /// 
        /// 操作"任務(wù)2"分組框的回調(diào)要執(zhí)行的方法
        /// 
        /// 
        private void ShowGroupTwo(string strValue)
        {
            this.gbJobTwo.Text = strValue;
        }
    }
}

原文鏈接：https://www.cnblogs.com/dotnet261010/p/6206068.html

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