具有自定义连接字符串的实体框架DbContext动态实例化 [英] Entity Framework DbContext dynamic instantiation with custom Connection String

问题描述

从ObjectContext迁移到DbContext代码生成后，我意识到生成的上下文类（继承自DbContext）没有构造函数，该构造函数既不接收 connectionString ，也不接收 EntityConnection （如ObjectContext子级

Migrating from ObjectContext to DbContext code-generation, I realized that context class generated (which inherits from DbContext) has no constructor that receives connectionString neither EntityConnection (like ObjectContext child class had).

这是我的应用程序中的一个问题，因为我需要使用运行时生成的连接字符串从具体Type动态实例化上下文。

This is a problem in my application since I need to instantiate my context dynamically from the concrete Type, using a runtime generated connection string.

推荐答案

在继承DbContext的类上，您应该能够指定采用连接字符串的基本构造函数：

On your class that inherits the DbContext, you should be able to specify the base constructor that takes the connection sting:

public class MyDbContext : DbContext
{
    public MyDbContext(string connString)
        : base(connString)
    {
    }
}

不过，您将必须使用SQLConnection构建器：

You will have to use the SQLConnection builder though:

SqlConnectionStringBuilder connBuilder= new SqlConnectionStringBuilder(dbConnString);

并在构造函数中使用它：

And use it in your constructor:

MyDbContext dbContext = new MyDbContext(connBuilder.ToString());

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