Question

随着新的ASP.NET 5取消了web.config，从而取消了ConfigurationManagement命名空间，我试图弄清楚如何从我的MVC应用程序中的数据访问层项目中读取连接字符串。

研究这个问题，我发现的所有内容都只是从Startup.cs文件中的project.json配置文件中读取配置值，如下所示：

var configuration = new Configuration();
configuration.AddJsonFile("config.json");
configuration.AddEnvironmentVariables();

//////

var connString = configuration.Get("Data:DefaultConnection:ConnectionString");

但我不希望我的网络项目与数据访问有任何关系。那么，我的数据访问层项目如何在此设置中检索连接字符串？

更新：这是我的startup.cs文件和ConfigureServices方法：

public void ConfigureServices(IServiceCollection services)
{
    // Add Identity services to the services container.
    services.AddIdentity<ApplicationUser, IdentityRole>()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    // Add MVC services to the services container.
    services.AddMvc();

    // Register application services.
    services.Configure<ApplicationOptions>(options =>
    {
        options.ConnectionString = "Data:DefaultConnection:ConnectionString";
    });
}

这是我的DataAccessLayer项目和我的RepoBase.cs类

public class RepoBase
{
    //private readonly string _connectionString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
    //private readonly string _connectionString = Environment.GetEnvironmentVariable("ConnectionString");
    private readonly string _connectionString;

    public RepoBase(IOptions<ApplicationOptions> appOptions)
    {
        this._connectionString = appOptions.ConnectionString;

        // or just read directly from System.Configuration.Get("");
    }

    protected SqlConnection GetConnection()
    {
        var conn = new SqlConnection(_connectionString);
        conn.OpenAsync();

        return conn;
    }
}

这是我在DAL项目中如何检索ApplicationOptions对象的空白，或者只是读取Startup.cs中设置的connectionstring值

configuration.AddEnvironmentVariables()

方法调用。

更新2：哦，这是我需要在数据访问层中使用来访问环境变量的内容：https://github.com/aspnet/configuration/blob/master/src/Microsoft.Extensions.Configuration.EnvironmentVariables/EnvironmentVariablesConfigurationProvider.cs

Answer 1

这是this

的副本

在ConfigureServices方法中，将配置对象添加为单例。

public void ConfigureServices(IServiceCollection services) {
    services.AddSingleton(_ => configuration);
}

然后像这样更新你的BaseRepo类

public class BaseRepo {
    private readonly IConfigurationRoot config;

    public BaseRepo(IConfigurationRoot config) {
        this.config = config;
    }

    public static SqlConnection GetOpenConnection() {
        var cs = config.Get<string>("Data:DefaultConnection:ConnectionString");
        var connection = new SqlConnection(cs);
        connection.Open();
        return connection;
    }
}

如何从asp.net 5中的数据访问层读取连接字符串

1 个答案: