asp.net-core – ASP.NET核心MVC应用程序设置

假设appsettings.json文件看起来像这样：

{
  "option1": "value1_from_json","ConnectionStrings": {
    "DefaultConnection": "Server=,SQL2016DEV;Database=DBName;Trusted_Connection=True"
  },"Logging": {
    "IncludeScopes": false,"LogLevel": {
      "Default": "Warning"
    }
  }
}

要从appsettings.json文件获取数据,首先需要在Startup.cs中设置ConfigurationBuilder,如下所示：

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);

    if (env.IsDevelopment())
    {
        // For more details on using the user secret store see https://go.microsoft.com/fwlink/?LinkID=532709
        builder.AddUserSecrets<Startup>();
    }

    builder.AddEnvironmentVariables();
    Configuration = builder.Build();

然后,您可以直接访问配置,但创建选项类来保存该数据更为全面,然后您可以将这些数据注入控制器或其他类.每个选项类都代表appsettings.json文件的不同部分.

在此代码中,连接字符串被加载到ConnectionStringSettings类中,另一个选项被加载到MyOptions类中. .GetSection方法获取appsettings.json文件的特定部分.再次,这是在Startup.cs：

public void ConfigureServices(IServiceCollection services)
{
    ... other code

    // Register the IConfiguration instance which MyOptions binds against.
    services.AddOptions();

    // Load the data from the 'root' of the json file
    services.Configure<MyOptions>(Configuration);

    // load the data from the 'ConnectionStrings' section of the json file
    var connStringSettings = Configuration.GetSection("ConnectionStrings");
    services.Configure<ConnectionStringSettings>(connStringSettings);

这些是设置数据加载到的类.请注意属性名称如何与json文件中的设置配对：

public class MyOptions
{
    public string Option1 { get; set; }
}

public class ConnectionStringSettings
{
    public string DefaultConnection { get; set; }
}

最后,您可以通过将OptionsAccessor注入控制器来访问这些设置,如下所示：

private readonly MyOptions _myOptions;

public HomeController(IOptions<MyOptions > optionsAccessor)
{
    _myOptions = optionsAccessor.Value;
    var valueOfOpt1 = _myOptions.Option1;
}

通常,Core中的整个配置设置过程非常不同. Thomas Ardal在他的网站上有一个很好的解释：http://thomasardal.com/appsettings-in-asp-net-core/

还有一个更详细的说明Configuration in ASP.NET Core in the Microsoft documentation.