ASP.NET核心2.1 Web API-配置管理器.ConnectionStrings返回空[重复]

string conString = Microsoft
   .Extensions
   .Configuration
   .ConfigurationExtensions
   .GetConnectionString(this.Configuration, "DefaultConnection");

System.Console.WriteLine(conString);

或者使用DI的结构化类:

public class SmtpConfig
{
    public string Server { get; set; }
    public string User { get; set; }
    public string Pass { get; set; }
    public int Port { get; set; }
}

启动:

public IConfigurationRoot Configuration { get; }


// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    // http://developer.telerik.com/featured/new-configuration-model-asp-net-core/
    // services.Configure<SmtpConfig>(Configuration.GetSection("Smtp"));
    Microsoft.Extensions.DependencyInjection.OptionsConfigurationServiceCollectionExtensions.Configure<SmtpConfig>(services, Configuration.GetSection("Smtp"));

public class HomeController : Controller
{

    public SmtpConfig SmtpConfig { get; }
    public HomeController(Microsoft.Extensions.Options.IOptions<SmtpConfig> smtpConfig)
    {
        SmtpConfig = smtpConfig.Value;
    } //Action Controller


    public IActionResult Index()
    {
        System.Console.WriteLine(SmtpConfig);
        return View();
    }

带着这个appsettings.json应用程序设置:

"ConnectionStrings": {
"DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-WebApplica71d622;Trusted_Connection=True;MultipleActiveResultSets=true"
},

"Smtp": {
    "Server": "0.0.0.1",
    "User": "user@company.com",
    "Pass": "123456789",
    "Port": "25"
  }

在启动.cs

public void ConfigureServices(IServiceCollection services)
{
    ...
    // Add the whole configuration object here.
    services.AddSingleton<IConfiguration>(Configuration);
}

private readonly IConfiguration configuration;

public HomeController(IConfiguration config) 
{
    configuration = config;
}

现在,稍后在视图代码中,您可以如下方式访问它:

connectionString = configuration.GetConnectionString("DefaultConnection");

更多信息请参见链接: https://docs.microsoft.com/en-us/ef/core/miscellaneous/connection-strings

    {
      "ConnectionStrings": {
        "BloggingDatabase": "Server=(localdb)\\mssqllocaldb;Database=EFGetStarted.ConsoleApp.NewDb;Trusted_Connection=True;"
      },
    }

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<BloggingContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("BloggingDatabase")));
}

我发现解决这个问题的方法是在启动时在构建器中使用AddJsonFile(它允许它找到存储在appsettings.json应用程序设置文件),然后使用它设置私有配置变量

public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddEnvironmentVariables();
        _config = builder.Build();
    }

然后我可以如下设置配置字符串:

var connectionString = _config.GetConnectionString("DbContextSettings:ConnectionString"); 

这是dotnet core 1.1上的

ASP.NET核心 ( 3.1款 )为我们提供 ,因此您可以简单地添加以下构造函数:

[Route("api/[controller]")]
[ApiController]
public class TestController : ControllerBase
{
    private readonly IConfiguration m_config;

    public TestController(IConfiguration config)
    {
        m_config = config;
    }

    [HttpGet]
    public string Get()
    {
        //you can get connection string as follows
        string connectionString = m_config.GetConnectionString("Default")
    }
}

{
    "ConnectionStrings": {
        "Default": "YOUR_CONNECTION_STRING"
        }
}

我有一个数据访问库,它可以与.net核心和.net框架一起工作。

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="conn1" connectionString="...." providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

配置管理器.ConnectionStrings-将读取连接字符串。

    var conn1 = ConfigurationManager.ConnectionStrings["conn1"].ConnectionString;

还有另一种方法。在我的示例中,您可以在repository类中看到一些业务逻辑,我在ASP.netmvccore3.1中使用了依赖注入。

我想在这里 connectiongString

此模式允许您在同一个业务逻辑存储库中访问不同的数据库。

public interface IStatsRepository
{
            IEnumerable<FederalDistrict> FederalDistricts();
}

class StatsRepository : IStatsRepository
{
   private readonly DbContextOptionsBuilder<EFCoreTestContext>
                optionsBuilder = new DbContextOptionsBuilder<EFCoreTestContext>();
   private readonly IConfigurationRoot configurationRoot;

   public StatsRepository()
   {
       IConfigurationBuilder configurationBuilder = new ConfigurationBuilder().SetBasePath(Environment.CurrentDirectory)
           .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
       configurationRoot = configurationBuilder.Build();
   }

   public IEnumerable<FederalDistrict> FederalDistricts()
   {
        var conn = configurationRoot.GetConnectionString("EFCoreTestContext");
        optionsBuilder.UseSqlServer(conn);

        using (var ctx = new EFCoreTestContext(optionsBuilder.Options))
        { 
            return ctx.FederalDistricts.Include(x => x.FederalSubjects).ToList();
        }
    }
}

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "EFCoreTestContext": "Data Source=DESKTOP-GNJKL2V\\MSSQLSERVER2014;Database=Test;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

https://docs.asp.net/projects/api/en/latest/autoapi/Microsoft/Extensions/Configuration/ConfigurationExtensions/index.html#Microsoft.Extensions.Configuration.ConfigurationExtensions.GetConnectionString