程序和启动类
.NET Core 2.x
您不需要IConfiguration在Startup构造函数中新建。它的实现将由DI系统注入。
// Program.cs
public class Program
{
public static void Main(string[] args)
{
BuildWebHost(args).Run();
}
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.Build();
}
// Startup.cs
public class Startup
{
public IHostingEnvironment HostingEnvironment { get; private set; }
public IConfiguration Configuration { get; private set; }
public Startup(IConfiguration configuration, IHostingEnvironment env)
{
this.HostingEnvironment = env;
this.Configuration = configuration;
}
}
.NET Core 1.x
您需要告诉Startup加载appsettings文件。
// Program.cs
public class Program
{
public static void Main(string[] args)
{
var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.UseApplicationInsights()
.Build();
host.Run();
}
}
//Startup.cs
public class Startup
{
public IConfigurationRoot Configuration { get; private set; }
public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
.AddEnvironmentVariables();
this.Configuration = builder.Build();
}
...
}
获得价值
您可以通过多种方法从应用程序设置中获取配置的值：
- 简单的使用方法
ConfigurationBuilder.GetValue<T>
- 使用选项模式
假设您的appsettings.json样子是这样的：
{
"ConnectionStrings": {
...
},
"AppIdentitySettings": {
"User": {
"RequireUniqueEmail": true
},
"Password": {
"RequiredLength": 6,
"RequireLowercase": true,
"RequireUppercase": true,
"RequireDigit": true,
"RequireNonAlphanumeric": true
},
"Lockout": {
"AllowedForNewUsers": true,
"DefaultLockoutTimeSpanInMins": 30,
"MaxFailedAccessAttempts": 5
}
},
"Recaptcha": {
...
},
...
}
简单方法
您可以将整个配置注入到控制器/类的构造函数中（通过IConfiguration），并使用指定的键获取所需的值：
public class AccountController : Controller
{
private readonly IConfiguration _config;
public AccountController(IConfiguration config)
{
_config = config;
}
[AllowAnonymous]
public IActionResult ResetPassword(int userId, string code)
{
var vm = new ResetPasswordViewModel
{
PasswordRequiredLength = _config.GetValue<int>(
"AppIdentitySettings:Password:RequiredLength"),
RequireUppercase = _config.GetValue<bool>(
"AppIdentitySettings:Password:RequireUppercase")
};
return View(vm);
}
}
选项模式
的ConfigurationBuilder.GetValue<T>，如果你只需要从应用程序设置一个或两个值的伟大工程。但是，如果您想从应用程序设置中获取多个值，或者不想在多个位置对这些键字符串进行硬编码，则使用Options Pattern可能会更容易。选项模式使用类来表示层次结构/结构。
要使用选项模式：
- 定义代表结构的类
- 注册那些类绑定到的配置实例
- 注入
IOptions<T>要获取值的控制器/类的构造函数
1.定义配置类以表示结构
您可以定义具有需要与您的应用程序设置中的键完全匹配的属性的类。类的名称不必与应用程序设置中的部分名称匹配：
public class AppIdentitySettings
{
public UserSettings User { get; set; }
public PasswordSettings Password { get; set; }
public LockoutSettings Lockout { get; set; }
}
public class UserSettings
{
public bool RequireUniqueEmail { get; set; }
}
public class PasswordSettings
{
public int RequiredLength { get; set; }
public bool RequireLowercase { get; set; }
public bool RequireUppercase { get; set; }
public bool RequireDigit { get; set; }
public bool RequireNonAlphanumeric { get; set; }
}
public class LockoutSettings
{
public bool AllowedForNewUsers { get; set; }
public int DefaultLockoutTimeSpanInMins { get; set; }
public int MaxFailedAccessAttempts { get; set; }
}
2.注册配置实例
然后，您需要ConfigureServices()在启动时注册此配置实例：
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
...
namespace DL.SO.UI.Web
{
public class Startup
{
...
public void ConfigureServices(IServiceCollection services)
{
...
var identitySettingsSection =
_configuration.GetSection("AppIdentitySettings");
services.Configure<AppIdentitySettings>(identitySettingsSection);
...
}
...
}
}
3.注入IOptions
最后，在要获取值的控制器/类上，需要IOptions<AppIdentitySettings>通过构造函数注入：
public class AccountController : Controller
{
private readonly AppIdentitySettings _appIdentitySettings;
public AccountController(IOptions<AppIdentitySettings> appIdentitySettingsAccessor)
{
_appIdentitySettings = appIdentitySettingsAccessor.Value;
}
[AllowAnonymous]
public IActionResult ResetPassword(int userId, string code)
{
var vm = new ResetPasswordViewModel
{
PasswordRequiredLength = _appIdentitySettings.Password.RequiredLength,
RequireUppercase = _appIdentitySettings.Password.RequireUppercase
};
return View(vm);
}
}