从vNext中的appsetting.json读取启动外的连接字符串

Question

我有一个项目类(Nuget Package).我需要在没有构造函数的静态类中读取我的连接字符串到MongoDB.

静态类方法:

        /// <summary>
        /// The default key MongoRepository will look for in the appsettings.json 
        /// </summary>
        private const string DefaultConnectionstringName = "Data:MongoDB:MongoServerSettings";

        /// <summary>
        /// Retrieves the default connectionstring from appsettings.json
        /// </summary>
        /// <returns>Returns the default connectionstring from the App.config or Web.config file.</returns>
        public static string GetDefaultConnectionString()
        {
            var config = new Configuration();
            return config.Get<string>(DefaultConnectionstringName);
        }

我总是null ...如何在不使用DI的情况下获取Startup.cs之外的值？

有可能的？

在我的旧代码中,我可以做类似的事情:

/// <summary>
    /// Retrieves the default connectionstring from the App.config or Web.config file.
    /// </summary>
    /// <returns>Returns the default connectionstring from the App.config or Web.config file.</returns>
    public static string GetDefaultConnectionString()
    {
        return ConfigurationManager.ConnectionStrings[DefaultConnectionstringName].ConnectionString;
    }

谢谢!!

Answer 1

1. appsetting.json中的.ConnectionString

2. 在Startup.cs类中创建Singleton Configuration of Configuration

3. 使用依赖注入从配置实例读取值[构造函数注入]

4. 最后输出

Answer 2

在启动内部,您应该将连接字符串保存到静态属性上 Startup

public class Startup
{
    public static string ConnectionString { get; private set; }

    public Startup(IHostingEnvironment env)
    {
        // Set up configuration sources.
        var builder = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddUserSecrets();

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

        builder.AddEnvironmentVariables();
        Configuration = builder.Build();
        ConnectionString = Configuration.Get<string>("Data:MongoDB:MongoServerSettings");
    }
    // ...
}

然后你应该能够从任何地方访问它:

public static string GetDefaultConnectionString()
{
    return Startup.ConnectionString;
}

Answer 3

这样的事情应该起作用：

   public Startup(IHostingEnvironment env, IApplicationEnvironment appEnv)
    {
        var builder = new ConfigurationBuilder(appEnv.ApplicationBasePath).AddJsonFile("config.json");
        Configuration = builder.Build();
        var connStr = Configuration.Get("connString");
    }

文件：http：//docs.asp.net/en/latest/fundamentals/configuration.html