在没有EF的情况下在appsettings.json中获取多个连接字符串 [英] Get Multiple Connection Strings in appsettings.json without EF

问题描述

通过迁移我开发的当前MVC .Net应用程序开始使用.Net Core RC2.在我看来，是因为使用appsettings.json处理配置的方式是:如果我有多个连接字符串，则要么必须使用EF来检索连接字符串，要么必须为每个连接字符串创建单独的类.我看到的所有示例都使用EF(对我而言这没有意义，因为我将使用Dapper)，或者该示例将构建一个以config中的部分命名的类.我是否缺少更好的解决方案?

Just starting playing with the .Net Core RC2 by migrating a current MVC .Net app I developed. It looks like to me because of the way that configuration is handled with appsettings.json that if I have multiple connection strings I either have to use EF to retrieve a connectionstring or I have to create separate classes named for each connection string. All the examples I see either use EF (which doesn't make sense for me since I will be using Dapper) or the example builds a class named after the section in the config. Am I missing a better solution?

    "Data": {
        "Server1": {
          "ConnectionString": "data source={server1};initial catalog=master;integrated security=True;"
        },
        "Server2": {
          "ConnectionString": "data source={server2};initial catalog=master;integrated security=True;"
        }
    }

为什么我要建立两个类，如果每个类的唯一属性是一个连接字符串，那么一个类就命名为"Server1"?

Why would I want to build two classes, one named "Server1" and another "Server2" if the only property each had was a connectionstring?

推荐答案

我对Adem对使用RC2的响应进行了一些更正，所以我认为最好将它们发布.

There are a couple of corrections that I made to Adem's response to work with RC2, so I figured I better post them.

我配置了appsettings.json并创建了一个类似于Adem的类

I configured the appsettings.json and created a class like Adem's

{
    "ConnectionStrings": {
      "DefaultConnectionString": "Default",
      "CustomConnectionString": "Custom"
    }
}

和

public class ConnectionStrings
{
    public string DefaultConnectionString { get; set; }

    public string CustomConnectionString { get; set; }
}

Adem的大多数代码都是VS for RC2的开箱即用，因此我只是将以下行添加到ConfigureServices方法中

most of Adem's code comes out of the box in VS for RC2, so I just added the line below to the ConfigureServices method

services.Configure<Models.ConnectionStrings>(Configuration.GetSection("ConnectionStrings"));

主要缺失点是必须将连接字符串传递给控制器​​(一旦您指定了强类型的配置对象并将其添加到服务集合中，就可以请求它通过请求IOptions实例 https:来从任何Controller或Action方法访问://docs.asp.net/en/latest/mvc/controllers/dependency-injection.html )

The main missing point is that the connection string has to be passed to the controller (Once you’ve specified a strongly-typed configuration object and added it to the services collection, you can request it from any Controller or Action method by requesting an instance of IOptions, https://docs.asp.net/en/latest/mvc/controllers/dependency-injection.html)

这要交给控制器了，

private readonly ConnectionStrings _connectionStrings;
        public HomeController(IOptions<ConnectionStrings> connectionStrings)
        {
            _connectionStrings = connectionStrings.Value;
        }

，然后在实例化DAL时传递适当的connectionString

and then when you instantiate the DAL you pass the appropriate connectionString

DAL.DataMethods dm = new DAL.DataMethods(_connectionStrings.CustomConnectionString);

所有示例都说明了这一点，但他们没有说明，为什么我直接从DAL中提取的尝试没有用

All the examples show this, they just don't state it, why my attempts to pull directly from the DAL didn't work

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