如何使用 .NET CORE 3.1 中的配置读取连接字符串

Question

我正在将我的代码从 .NET CORE 2.2 迁移到 .NET CORE 3.1。从 appsettings.json 读取连接字符串时遇到以下错误

“'Configuration' 不包含 'GetConnectionString' 的定义”

我在 startup.cs 中使用下面的代码

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
    services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
}

我的 appsettings.json 如下

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },

  "ConnectionStrings": {
    "DefaultConnection": "Data Source=abc.net;Initial Catalog=xyz;User ID=paper;Password=pencil"
  },
  "AllowedHosts": "*",

  "serverSigningPassword": "key",
  "accessTokenDurationInMinutes": 2
}

有什么方法可以读取appsettings.json中的这个连接字符串和其他变量

Answer 1

有几点需要注意，

你注入构造函数了吗？

public Startup(IConfiguration configuration)
{
  Configuration = configuration;
}

public IConfiguration Configuration { get; }

并将其用作

 public void ConfigureServices(IServiceCollection services)
  {
     var connection = Configuration.GetConnectionString("DefaultConnection");
     services.AddDbContext<ShelterPZ_DBContext>(options => options.UseSqlServer(connection));
     services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
  }