.Net6 winform 程序使用依賴注入

.net  Blazor webassembly 和 webAPI 內建支持依賴注入, Winform 和 Console 應用雖然不帶有依賴注入功能, 但增加依賴注入也很簡單. 

本文將示例如何為 WinForm 程序增加依賴注入特性, 實現通過DI容器獲取Cofiguration 實例, 並讀取appsettings.json文件.

 

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安裝依賴庫, 有點多

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Microsoft.Extensions.DependencyInjection 庫, 依賴注入的類庫

Microsoft.Extensions.Configuration 庫, 包含IConfiguration接口 和 Configuration類

Microsoft.Extensions.Configuration.Json 庫, 為 IConfiguration 增加了讀取 Json 文件功能,

Microsoft.Extensions.Hosting 庫,  提供 Host 靜態類,  有能力從 appsettings.{env.EnvironmentName}.json 加載相應 env  的設定值,  並將設定值用於IConfiguration/ILoggerFactory中, 同時增加 Console/EventSourceLogger 等 logger. 僅適用於 Asp.Net core 和 Console 類應用

Microsoft.Extensions.Logging 庫,  包含 ILogger 和 ILoggerFactory 接口

Serilog.Extensions.Logging 庫, 為DI 容器提供 AddSerilog() 方法.

Serilog.Sinks.File 庫, 提供 Serilog rolling logger

Serilog.Sinks.Console 庫, 增加 serilog console logger

Serilog.Settings.Configuration 庫, 允許在 appsetting.json  配置 Serilog, 頂層節點要求是 Serilog. 

Serilog.Enrichers.Thread 和 Serilog.Enrichers.Environment 庫,  為輸出日志文本增加 Thread和 env 信息

補充庫:

• Microsoft.Extensions.Options.ConfigurationExtensions 庫,  為DI容器增加了從配置文件中實例化對象的能力, 即  serviceCollection.Configure<TOptions>(IConfiguration)
• Microsoft.Extensions.Options 庫,  提供以強類型的方式讀取configuration文件, 這是.Net中首選的讀取configuration文件方式.

 

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appsettings.json 配置文件

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配置一個 ConnectionString, 另外配 serilog

{
  
  "ConnectionStrings": {
    "oeeDb": "Server=localhost\\SQLEXPRESS01;Database=Oee;Trusted_Connection=True;"
  },

  "Serilog": {
    "Using": [ "Serilog.Sinks.Console", "Serilog.Sinks.File" ],
    "MinimumLevel": "Debug",
    "WriteTo": [
      { "Name": "Console" },
      {
        "Name": "File",
        "Args": { "path": "Logs/serilog.txt" }
      }
    ],
    "Enrich": [ "FromLogContext", "WithMachineName", "WithThreadId" ]
  }
}

 

 

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Program.cs , 增加DI容器

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using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

using Serilog;

namespace Collector
{
    internal static class Program
    {
        /// <summary>
        ///  The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            ApplicationConfiguration.Initialize();
            //未使用依賴注入的寫法
            //Application.Run(new FormMain());
 
            
           //生成 DI 容器
           ServiceCollection services = new ServiceCollection();
           ConfigureServices(services);  //注冊各種服務類

            //先用DI容器生成 serviceProvider, 然后通過 serviceProvider 獲取Main Form的注冊實例
           var serviceProvider =services.BuildServiceProvider();
            
           var formMain = serviceProvider.GetRequiredService<FormMain>();   //主動從容器中獲取FormMain實例, 這是簡潔寫法
           // var formMain = (FormMain)serviceProvider.GetService(typeof(FormMain));  //更繁瑣的寫法
           Application.Run(formMain); 
        }

       
        /// <summary>
        /// 在DI容器中注冊所有的服務類型 
        /// </summary>
        /// <param name="services"></param>
        private static void ConfigureServices(ServiceCollection services)
        {
            //注冊 FormMain 類
            services.AddScoped<FormMain>();

            //register configuration
            IConfigurationBuilder cfgBuilder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile($"appsettings.{Environment.GetEnvironmentVariable("DOTNET_ENVIRONMENT")}.json", optional: true, reloadOnChange: false)
                ;
            IConfiguration configuration=cfgBuilder.Build();
            services.AddSingleton<IConfiguration>(configuration);

            //Create logger instance
            var serilogLogger = new LoggerConfiguration()
                .ReadFrom.Configuration(configuration)
                .Enrich.FromLogContext()
                .CreateLogger();

            //register logger
            services.AddLogging(builder => {
                object p = builder.AddSerilog(logger: serilogLogger, dispose: true);
            });

        }
    } 
}

 

 

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FormMain.cs , 驗證依賴注入的效果

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using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace Collector
{
    public partial class FormMain : Form
    { 
        private readonly IConfiguration _configuration; 
        private readonly ILogger _logger;

        /// <summary>
        /// 為 FormMain 構造子增加兩個形參, 構造子參數將由於DI容器自動注入
        /// </summary>
        /// <param name="configuration"></param>
        /// <param name="logger">形參必須是 ILogger泛型類型, 不能是 ILogger 類型</param>
        public FormMain(IConfiguration configuration, ILogger<FormMain> logger)  
        {
            _configuration = configuration;
            _logger = logger;

            InitializeComponent();
            var connectionString = _configuration.GetConnectionString("oeeDb");  //從配置文件中讀取oeeDb connectionString 
            _logger.LogInformation(connectionString);   //將connection String 寫入到日志文件中
        }

    }
}

 

 

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DI容器管理配置文件Section

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上面示例, 我們通過 _configuration.GetConnectionString("oeeDb")  可以拿到connectionString, 非常方便, 這主要是得益於.Net 已經類庫已經考慮到在配置文件中存儲 connectionString 是一個普遍的做法, 所以類庫內置支持了.

如果在 appsettings.json 中存一些自定義的信息, 如何方便讀取呢? 微軟推薦的 Options 模式, 下面詳細介紹.

首先安裝庫:

• Microsoft.Extensions.Options.ConfigurationExtensions 庫,  為DI容器增加了從配置文件中實例化對象的能力, 即  serviceCollection.Configure<TOptions>(IConfiguration)
• Microsoft.Extensions.Options 庫,  提供以強類型的方式讀取configuration文件, 這是.Net中首選的讀取configuration文件方式.

假設 appsettings.json 中要存放appKey和appSecret信息, 具體配置如下:

  "AppServiceOptions": {
    "appKey": "appkey1",
    "appSecret": "appSecret1"
  }

定義對應的 Poco Class,  推薦后綴為 Options,

    public class AppServiceOptions
    {
        public string AppKey { get; set; } = "";
        public string AppSecret { get; set; } = "";

    }

 

注冊函數 ConfigureServices()中,  注冊 AppServiceOptions 類, 告知DI容器, 要基於配置文件AppServiceOptions section來實例化

        private static void ConfigureServices(ServiceCollection services)
        {
            //注冊 FormMain 類
            services.AddScoped<FormMain>();

            //register configuration
            IConfigurationBuilder cfgBuilder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile($"appsettings.{Environment.GetEnvironmentVariable("DOTNET_ENVIRONMENT")}.json", optional: true, reloadOnChange: false)
                ;
            IConfiguration configuration=cfgBuilder.Build();
            services.AddSingleton<IConfiguration>(configuration);

            //Create logger instance
            var serilogLogger = new LoggerConfiguration()
                .ReadFrom.Configuration(configuration)
                .Enrich.FromLogContext()
                .CreateLogger();

            //register logger, 如果使用內置的 logger, 只需調用 services.AddLogging() 即可. 
            services.AddLogging(builder => {
                object p = builder.AddSerilog(logger: serilogLogger, dispose: true);
            });


            //注冊 AppServiceOptions 類, 告知DI容器, 要基於配置文件AppServiceOptions section來實例化
 services.AddOptions(); services.Configure<AppServiceOptions>(configuration.GetSection("AppServiceOptions"));    
        }

 

主動從DI容器中獲取 AppServiceOptions 配置信息代碼如下, 注意GetRequiredService函數的的泛型參數要使用 IOptions<> 包一下.

   var appServiceOptionsWrapper=serviceProvider.GetRequiredService<IOptions<AppServiceOptions>>();
   AppServiceOptions appServiceOptions= appServiceOptionsWrapper.Value;

 

將 AppServiceOptions 注入到 FormMain 的代碼, 和主動從DI容器中獲取 AppServiceOptions 實例一樣, 都需要使用 IOptions<> 接口包一下構造子形參.

    public partial class FormMain : Form
    { 
        private readonly IConfiguration _configuration; 
        private readonly ILogger _logger;
        private AppServiceOptions _appServiceOptions;

        /// <summary>
        /// 為 FormMain 構造子增加三個形參, 構造子參數將由於DI容器自動注入
        /// </summary>
        /// <param name="configuration">形參必須是接口 IConfigurations</param>
        /// <param name="logger">形參必須是 ILogger泛型類型, 不能是 ILogger 類型</param>
        /// <param name="appServiceOptionsWrapper">形參必須是 IOptions 泛型接口 </param>
        public FormMain(IConfiguration configuration, ILogger<FormMain> logger, IOptions<AppServiceOptions> appServiceOptionsWrapper)  
        {
            _configuration = configuration;
            _logger = logger;
            _appServiceOptions = appServiceOptionsWrapper.Value;

            InitializeComponent(); 
            var connectionString = _configuration.GetConnectionString("oeeDb");  //從配置文件中讀取oeeDb connectionString 
            _logger.LogInformation(connectionString);   //將connection String 寫入到日志文件中
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Text = _appServiceOptions.AppKey;
        }
    }

 

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.net core 復雜 configuration Section 的讀取

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appsettings文件定義一個復雜的設置項, 頂層是一個json 數組, 里面又嵌套了另一個數組

  "PlcDevices": [
    {
      "PlcDeviceId": "Plc1",
      "IpAddress": "127.0.0.1",
      "Port": 1234,
      "SlaveId": 1,
      "DataPoints": [
        {
          "ModbusAddress": 0,
          "EqpId": "eqp1"
        },
        {
          "ModbusAddress": 0,
          "EqpId": "eqp2"
        }
      ]
    },

    {
      "PlcDeviceId": "Plc2",
      "IpAddress": "127.0.0.2",
      "Port": 1234,
      "SlaveId": "2",
      "DataPoints": [
        {
          "ModbusAddress": 0,
          "EqpId": "eqp3"
        },
        {
          "ModbusAddress": 0,
          "EqpId": "eqp4"
        }
      ]
    }
  ]

 

對應poco對象為:

public class PlcDevice
{
    public string IpAddress { get; set; } = "";
    public int Port { get; set; } = 0;
    public string PlcDeviceId { get; set; } = "";
    public int SlaveId { get; set; } 
    public List<DataPoint> DataPoints { get; set; }

}

public class DataPoint
{  public int ModbusAddress { get; set; }
    public string EqpId { get; set; } = "";
}

 

讀取 json 的C# 代碼:

services.AddOptions();
//實例化一個對應 PlcDevices json 數組對象, 使用了 IConfiguration.Get<T>()
var PlcDeviceSettings= configuration.GetSection("PlcDevices").Get<List<PlcDevice>>();
//或直接通過 service.Configure<T>() 將appsettings 指定 section 放入DI 容器, 這里的T 為 List<PlcDevice>
services.Configure<List<PlcDevice>>(configuration.GetSection("PlcDevices"));