开源 C# 快速开发（十）通讯--http客户端
文章的目的为了记录使用C# 开发学习的经历。开发流程和要点有些记忆模糊，赶紧记录，防止忘记。
相关链接：
开源 C# 快速开发（一）基础知识
开源 C# 快速开发（二）基础控件
开源 C# 快速开发（三）复杂控件
开源 C# 快速开发（四）自定义控件--波形图
开源 C# 快速开发（五）自定义控件--仪表盘
开源 C# 快速开发（六）自定义控件--圆环
开源 C# 快速开发（七）通讯--串口
开源 C# 快速开发（八）通讯--Tcp服务器端
开源 C# 快速开发（九）通讯--Tcp客户端
开源 C# 快速开发（十）通讯--http客户端
推荐链接:
开源 C# .net mvc 开发（一）WEB搭建_c#部署web程序-CSDN博客
开源 C# .net mvc 开发（二）网站快速搭建_c#网站开发-CSDN博客
开源 C# .net mvc 开发（三）WEB内外网访问-CSDN博客
开源 C# .net mvc 开发（四）工程结构、页面提交以及显示-CSDN博客
开源 C# .net mvc 开发（五）常用代码快速开发_c# mvc开发-CSDN博客
开源 C# .net mvc 开发（六）发送邮件、定时以及CMD编程-CSDN博客
开源 C# .net mvc 开发（七）动态图片、动态表格和json数据生成-CSDN博客
开源 C# .net mvc 开发（八）IIS Express轻量化Web服务器的配置和使用-CSDN博客
开源 C# .net mvc 开发（九）websocket--服务器与客户端的实时通信-CSDN博客
本章节主要内容是:HTTP 客户端示例，使用 WinForms 异步编程和 HTTP 请求处理。
目录：
1.源码分析
2.所有源码
3.效果演示
一、源码分析1. 命名空间和引用分析
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net.Http; // HTTP客户端功能
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms; // WinForms UI组件namespace _9_http
{// 主窗体类public partial class Form1 : Form
作用：引入了必要的命名空间，特别是：System.Net.Http：提供HttpClient等HTTP功能System.Windows.Forms：提供WinForms UI组件2. 类成员变量声明
private TextBox txtUrl; // URL输入框
private TextBox txtResult; // 结果显示框
private Button btnGet; // GET请求按钮
private Button btnPost; // POST请求按钮
private HttpClient httpClient; // HTTP客户端实例
作用：声明了窗体所需的UI组件和HTTP客户端实例。3. 构造函数分析
3.1 主要构造函数
功能：
初始化窗体组件
创建HttpClient单例
设置User-Agent头避免被网站拒绝
public Form1()
{InitializeComponent(); // 初始化设计器生成的组件init(); // 调用自定义初始化方法httpClient = new HttpClient(); // 创建HttpClient实例// 设置默认请求头（伪装浏览器）httpClient.DefaultRequestHeaders.Add("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");
}3.2 初始化方法 init()
private void init()
{// URL输入框初始化txtUrl = new TextBox();txtUrl.Text = "https://www.hao123.com/"; // 默认URLtxtUrl.Location = new System.Drawing.Point(12, 12); // 位置txtUrl.Size = new System.Drawing.Size(400, 23); // 尺寸// 结果文本框初始化txtResult = new TextBox();txtResult.Multiline = true; // 多行模式txtResult.ScrollBars = ScrollBars.Both; // 水平和垂直滚动条txtResult.Location = new System.Drawing.Point(12, 45);txtResult.Size = new System.Drawing.Size(600, 300);txtResult.WordWrap = false; // 禁用自动换行// GET按钮初始化btnGet = new Button();btnGet.Text = "GET请求";btnGet.Location = new System.Drawing.Point(420, 11);btnGet.Size = new System.Drawing.Size(80, 25);btnGet.Click += BtnGet_Click; // 绑定点击事件// POST按钮初始化btnPost = new Button();btnPost.Text = "POST请求";btnPost.Location = new System.Drawing.Point(510, 11);btnPost.Size = new System.Drawing.Size(80, 25);btnPost.Click += BtnPost_Click; // 绑定点击事件// 窗体设置this.Text = "HTTP请求示例"; // 窗体标题this.ClientSize = new System.Drawing.Size(624, 361); // 窗体尺寸this.Controls.AddRange(new Control[] { txtUrl, txtResult, btnGet, btnPost });
}
4. GET请求处理函数 BtnGet_Click
执行流程：
输入验证 → 显示状态 → 设置超时 → 发送请求 → 检查状态 → 读取内容 → 格式化显示
private async void BtnGet_Click(object sender, EventArgs e)
{// 1. URL验证if (string.IsNullOrWhiteSpace(txtUrl.Text)){MessageBox.Show("请输入URL");return;}try{// 2. 显示请求状态txtResult.Text = "请求中...";// 3. 设置超时时间（30秒）httpClient.Timeout = TimeSpan.FromSeconds(30);// 4. 发送异步GET请求（核心代码）HttpResponseMessage response = await httpClient.GetAsync(txtUrl.Text);// 5. 检查HTTP状态码（非2xx会抛出异常）response.EnsureSuccessStatusCode();// 6. 读取响应内容string content = await response.Content.ReadAsStringAsync();// 7. 格式化并显示结果txtResult.Text = FormatResponse(response, content);}catch (HttpRequestException ex) // HTTP相关异常{txtResult.Text = $"HTTP错误: {ex.Message}";}catch (TaskCanceledException) // 超时异常{txtResult.Text = "请求超时";}catch (Exception ex) // 其他异常{txtResult.Text = $"错误: {ex.Message}";}
}
5. POST请求处理函数 BtnPost_Click
POST数据细节：
内容：{"key":"value"}
编码：UTF-8
内容类型：application/json
private async void BtnPost_Click(object sender, EventArgs e)
{// 1. URL验证if (string.IsNullOrWhiteSpace(txtUrl.Text)){MessageBox.Show("请输入URL");return;}try{// 2. 显示请求状态txtResult.Text = "请求中...";// 3. 创建POST数据（固定JSON格式）var postData = new StringContent("{\"key\":\"value\"}",System.Text.Encoding.UTF8, "application/json");// 4. 发送异步POST请求HttpResponseMessage response = await httpClient.PostAsync(txtUrl.Text, postData);// 5. 检查HTTP状态码response.EnsureSuccessStatusCode();// 6. 读取响应内容string content = await response.Content.ReadAsStringAsync();// 7. 格式化并显示结果txtResult.Text = FormatResponse(response, content);}catch (Exception ex) // 统一异常处理{txtResult.Text = $"错误: {ex.Message}";}
}6. 响应格式化函数 FormatResponse
private string FormatResponse(HttpResponseMessage response, string content)
{return $"状态码: {(int)response.StatusCode} {response.StatusCode}\n" +$"响应头:\n{response.Headers}\n\n" +$"响应内容:\n{content}";
}输出格式：
状态码: 200 OK
响应头:
HeaderName1: Value1
HeaderName2: Value2
响应内容:
<html>...网页内容...</html>
二、所有源码
Form1.designer.cs界面文件
namespace _9_http
{partial class Form1{/// <summary>/// 必需的设计器变量。/// </summary>private System.ComponentModel.IContainer components = null;/// <summary>/// 清理所有正在使用的资源。/// </summary>/// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>protected override void Dispose(bool disposing){if (disposing && (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 - 不要修改/// 使用代码编辑器修改此方法的内容。/// </summary>private void InitializeComponent(){// // Form1// this.AutoScaleDimensions = new System.Drawing.SizeF(9F, 18F);this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;this.ClientSize = new System.Drawing.Size(1219, 974);this.Name = "Form1";this.Text = "Form1";this.ResumeLayout(false);this.PerformLayout();}#endregionprivate System.Windows.Forms.Button button1;private System.Windows.Forms.RichTextBox richTextBox1;private System.Windows.Forms.TextBox txtName;private System.Windows.Forms.TextBox txtPwd;}
}Form1.cs文件
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace _9_http
{public partial class Form1 : Form{/*public Form1(){InitializeComponent();}*/private TextBox txtUrl;private TextBox txtResult;private Button btnGet;private Button btnPost;private HttpClient httpClient;public Form1(){InitializeComponent();init();httpClient = new HttpClient();// 设置默认请求头（可选）httpClient.DefaultRequestHeaders.Add("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");}private void init(){// URL输入框txtUrl = new TextBox();txtUrl.Text = "https://www.hao123.com/";txtUrl.Location = new System.Drawing.Point(12, 12);txtUrl.Size = new System.Drawing.Size(400, 23);// 结果文本框txtResult = new TextBox();txtResult.Multiline = true;txtResult.ScrollBars = ScrollBars.Both;txtResult.Location = new System.Drawing.Point(12, 45);txtResult.Size = new System.Drawing.Size(600, 300);txtResult.WordWrap = false;// 按钮btnGet = new Button();btnGet.Text = "GET请求";btnGet.Location = new System.Drawing.Point(420, 11);btnGet.Size = new System.Drawing.Size(80, 25);btnGet.Click += BtnGet_Click;btnPost = new Button();btnPost.Text = "POST请求";btnPost.Location = new System.Drawing.Point(510, 11);btnPost.Size = new System.Drawing.Size(80, 25);btnPost.Click += BtnPost_Click;// 窗体设置this.Text = "HTTP请求示例";this.ClientSize = new System.Drawing.Size(624, 361);this.Controls.AddRange(new Control[] { txtUrl, txtResult, btnGet, btnPost });}private async void BtnGet_Click(object sender, EventArgs e){if (string.IsNullOrWhiteSpace(txtUrl.Text)){MessageBox.Show("请输入URL");return;}try{txtResult.Text = "请求中...";// 设置超时时间httpClient.Timeout = TimeSpan.FromSeconds(30);HttpResponseMessage response = await httpClient.GetAsync(txtUrl.Text);response.EnsureSuccessStatusCode();string content = await response.Content.ReadAsStringAsync();txtResult.Text = FormatResponse(response, content);}catch (HttpRequestException ex){txtResult.Text = $"HTTP错误: {ex.Message}";}catch (TaskCanceledException){txtResult.Text = "请求超时";}catch (Exception ex){txtResult.Text = $"错误: {ex.Message}";}}private async void BtnPost_Click(object sender, EventArgs e){if (string.IsNullOrWhiteSpace(txtUrl.Text)){MessageBox.Show("请输入URL");return;}try{txtResult.Text = "请求中...";// 创建POST内容var postData = new StringContent("{\"key\":\"value\"}",System.Text.Encoding.UTF8, "application/json");HttpResponseMessage response = await httpClient.PostAsync(txtUrl.Text, postData);response.EnsureSuccessStatusCode();string content = await response.Content.ReadAsStringAsync();txtResult.Text = FormatResponse(response, content);}catch (Exception ex){txtResult.Text = $"错误: {ex.Message}";}}private string FormatResponse(HttpResponseMessage response, string content){return $"状态码: {(int)response.StatusCode} {response.StatusCode}\n" +$"响应头:\n{response.Headers}\n\n" +$"响应内容:\n{content}";}protected override void OnFormClosing(FormClosingEventArgs e){httpClient?.Dispose();base.OnFormClosing(e);}}
}三、效果演示
输入https://www.hao123.com/，点击Post请求，可以获得hao123网址的回应。
