实现 WebApi 自托管服务宿主于 WinForms 及其交互

在 Windows 平台 Web 服务一般托管于 IIS. 在开发中, 会遇到 WinForms 或 WPF 服务端程序需要提供对外 API 作为服务. 在本文详细介绍 WebApi 自托管于 WinForms 中, WPF 或 Console 程序实现类似.

0. 完整示例演示#

1. 新建解决方案以及 WinForms 工程#

1.1. 新建解决方案及工程#

如下图所示:

• 建立空白解决方案及 Winforms 工程,
• 新建 Controllers 文件夹用于存放 WebApi 代码,
• 新建 Services 文件夹用于存放服务代码.

1.2. 拖拽控件#

绘制必要控件, 布局如下:

备注: 绘制一个 NumericUpDown 和两个 Button 控件.

1.3. 引用相关开发包:#

• Microsoft.AspNet.WebApi.Client
• Microsoft.AspNet.WebApi.Core
• Microsoft.AspNet.WebApi.SelfHost

2. 开发 HTTP 服务类#

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/// <summary> /// HTTP service. /// </summary> public class HttpService : IDisposable { /// <summary> /// HTTP server's listening port. /// </summary> public int Port { get; set; } /// <summary> /// HTTP self hosting. /// </summary> private readonly HttpSelfHostServer _server; /// <summary> /// HTTP server. /// </summary> /// <param name="port">Listening port.</param> public HttpService(int port) { this.Port = port; var config = new HttpSelfHostConfiguration($"http://0.0.0.0:{this.Port}"); config.MapHttpAttributeRoutes(); config.Routes.MapHttpRoute("DefaultApi", "api/{controller}/{action}"); _server = new HttpSelfHostServer(config); } #region HTTP Service /// <summary> /// start HTTP server. /// </summary> public Task StartHttpServer() { return _server.OpenAsync(); } /// <summary> /// Close HTTP server. /// </summary> public Task CloseHttpServer() { return _server.CloseAsync(); } #endregion /// <summary> /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. /// </summary> public void Dispose() { _server?.Dispose(); } }

WebApi 自托管服务主要由 HttpSelfHostServer 实现, 其 OpenAsync 开启 HTTP 监听, CloseAsync 关闭 HTTP 监听.

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config.MapHttpAttributeRoutes();

可以在 Controller 中使用路由特性.

3. 调用 HTTP 服务#

在 MainForm 窗体程序中引用 HTTP 服务:

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public class MainForm:Form { /// <summary> /// Http service. /// </summary> private HttpService _http; }

3.1. 编写开启 HTTP 服务代码#

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/// <summary> /// start the http server. /// </summary> private async void StartButton_Click(object sender, EventArgs e) { /** * start. */ try { var port = Convert.ToInt32(this.PortNum.Value); /** * initialize http service. */ _http = new HttpService(port); await _http.StartHttpServer(); } catch (Exception exception) { MessageBox.Show($"{exception.Message}", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } }

3.2. 编写关闭 HTTP 服务代码#

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/// <summary> /// close the http server. /// </summary> private async void CloseButton_Click(object sender, EventArgs e) { /** * close. */ try { await _http.CloseHttpServer(); _http.Dispose(); } catch (Exception exception) { MessageBox.Show($"{exception.Message}", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } }

4. 开发控制器#

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/// <summary> /// Home controller. /// </summary> [RoutePrefix("api/home")] public class HomeController : ApiController { /// <summary> /// Print the greetings /// </summary> /// <param name="name">visitor</param> /// <returns>greetings</returns> [Route("echo")] [HttpGet] public IHttpActionResult Echo(string name) { return Json(new {Name = name, Message = $"Hello, {name}"}); } }

5. 合在一起#

下载完整示例代码 (GitHub)

6. 注意事项#

程序需要拥有 管理员权限 才能开启 HTTP 监听, 在调试时, 若 Visual Studio 为拥有管理员权限, 则无法正常运行. 同样地, 在程序编译生成之后运行时亦需要权限.