浅析.netcore中的Configuration具体使用

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration(configure => {               
                configure.AddJsonFile("config.json");  //无法热修改

            })
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((context,configure) => {
            Dictionary<string, string> memoryConfig = new Dictionary<string, string>();
            memoryConfig.Add("memoryKey1", "m1");
            memoryConfig.Add("memoryKey2", "m2");
    
            configure.AddInMemoryCollection(memoryConfig);
    
        })
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });

Host.CreateDefaultBuilder(args)    
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
    });


//CreateDefaultBuilder源码
public static IHostBuilder CreateDefaultBuilder(string[] args)
{
    var builder = new HostBuilder();

    builder.UseContentRoot(Directory.GetCurrentDirectory());
    builder.ConfigureHostConfiguration(config =>
    {
        config.AddEnvironmentVariables(prefix: "dotnet_");
        if (args != null)
        {
            config.AddCommandLine(args);
        }
    });

    builder.ConfigureAppConfiguration((hostinGContext, config) =>
    {
        var env = hostingContext.HostingEnvironment;

        config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
              .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true);

        if (env.IsDevelopment() && !string.IsNullOrEmpty(env.ApplicationName))
        {
            var appAssembly = Assembly.Load(new AssemblyName(env.ApplicationName));
            if (appAssembly != null)
            {
                config.AddUserSecrets(appAssembly, optional: true);
            }
        }

        config.AddEnvironmentVariables();

        if (args != null)
        {
            config.AddCommandLine(args);
        }
    });
    
    ....

    return builder;
}

public static void Main(string[] args)
{
    CreateHostBuilder(args).Build().Run();
}
//以下为部分源码
private List<Action<HostBuilderContext, IConfigurationBuilder>> _configureAppConfigActions = new List<Action<HostBuilderContext, IConfigurationBuilder>>();private IConfiguration _appConfiguration;

public IHostBuilder ConfigureAppConfiguration(Action<HostBuilderContext, IConfigurationBuilder> configureDelegate)
{
    _configureAppConfigActions.Add(configureDelegate ?? throw new ArgumentNullException(nameof(configureDelegate)));
    return this;
}


public IHost Build()
{
    ...

    BuildAppConfiguration();

    ...
}

private void BuildAppConfiguration()
{
    var configBuilder = new ConfigurationBuilder()
        .SetBasePath(_hostingEnvironment.ContentRootPath)
        .AddConfiguration(_hostConfiguration, shouldDisposeConfiguration: true);

    foreach (var buildAction in _configureAppConfigActions)
    {
        buildAction(_hostBuilderContext, configBuilder);
    }
    _appConfiguration = configBuilder.Build();
    _hostBuilderContext.Configuration = _appConfiguration;
}

"config_key2": {
    "config_key2_1": "config_key2_1",
    "config_key2_2": "config_key2_2"
  }

"Student": {
    "Sno": "SNO",
    "Sname": "SNAME",
    "Sage": 18,
    "ID": "001"
  }

public class Student
{
    private string _id;
    public const string Name = "Student";
    private string ID { get; set; }
    public string Sno { get; set; }
    public string Sname { get; set; }
    public int Sage { get; set; }
}

Student student = new Student();
_configuration.GetSection(Student.Name).Bind(student);

var student1 = _configuration.GetSection(Student.Name).Get<Student>(binderOptions=> {
　　binderOptions.BindNonPublicProperties = true;
});

services.Configure<Student>(Configuration.GetSection(Student.Name));

private readonly ILogger<WeatherForecastController> _logger;
private readonly IConfiguration _configuration;
private readonly Student _student;

public WeatherForecastController(ILogger<WeatherForecastController> logger, IConfiguration configuration, IOptions<Student> student)
{
    _logger = logger;
    _configuration = configuration;
    _student = student.Value;
}

"Root": {
  "child1": {
    "child_1": "child1_1",
    "child_2": "child1_2"
  },
  "child2": {
    "child_1": "child2_1",
    "child_2": "child2_2"
  }
}public class Root{　　public string child_1{get;set;}　　public string child_2{get;set;}}

services.Configure<Root>("Child1",Configuration.GetSection("Root:child1"));
services.Configure<Root>("Child2", Configuration.GetSection("Root:child2"));

private readonly ILogger<WeatherForecastController> _logger;
private readonly IConfiguration _configuration;
private readonly Student _student;
private readonly Root _child1;
private readonly Root _child2;

public WeatherForecastController(ILogger<WeatherForecastController> logger, IConfiguration configuration, IOptions<Student> student,IOptionsSnapshot<Root> root)
{
    _logger = logger;
    _configuration = configuration;
    _student = student.Value;
    _child1 = root.Get("Child1");
    _child2 = root.Get("Child2");
}