EntityFramework 6 基于代码的数据库优先连接字符串配置 [英] EntityFramework 6 Code-based configuration of connection string for database-first

问题描述

我正在尝试使现有应用程序在没有 app.config 的情况下工作(由于非常特定的环境而需要它).问题是它严重依赖 EntityFramework 6 来处理 SQL-Server.

I'm attempting to make an existing application work without an app.config (it is required due to a very specific environment). Problem is that it's heavily relying on EntityFramework 6 to work with an SQL-Server.

我正在尝试使用 基于代码的配置，但我不知道如何通过我的配置类提供正确的连接字符串.

I'm trying to use a code-based configuration, but I can't figure out how to provide a correct connection string through my configuration class.

我做了一个配置类:

public class MyConfiguration : DbConfiguration
{
    public MyConfiguration()
    {
        SetDefaultConnectionFactory(new MyConnectionFactory());
        SetProviderServices("System.Data.SqlClient", System.Data.Entity.SqlServer.SqlProviderServices.Instance);
    }
}

然后将其提供给我的 DbContext(由 EF 自动从 bd 生成):

Then provided it to my DbContext (Generated by EF automatically from bd):

[DbConfigurationType(typeof(MyConfiguration))]
public partial class TestModelEntities
{           
}

使用自定义连接工厂:

public class MyConnectionFactory : IDbConnectionFactory
{
    public DbConnection CreateConnection(string nameOrConnectionString)
    {
        var newConnStringBuilder = new SqlConnectionStringBuilder
        {
            UserID = "user",
            Password = "pass",
            InitialCatalog = "databaseName",
            DataSource = "serverName"
        };

        var entityConnectionBuilder = new EntityConnectionStringBuilder
        {
            Provider = "System.Data.SqlClient",
            ProviderConnectionString = newConnStringBuilder.ToString(),
            Metadata = @"res://*/TestModel.csdl|
                            res://*/TestModel.ssdl|
                            res://*/TestModel.msl"
        };

        var newDbConnect = new EntityConnection(entityConnectionBuilder.ToString());
        return newDbConnect;
    }
}

但是.当我测试它时，我得到一个 UnintentionalCodeFirstException.为什么?我错过了什么?

However. When I test it, I get an UnintentionalCodeFirstException. Why? What am I missing?

推荐答案

你应该通过 :base(connectionString) 为你的上下文提供连接字符串.如下创建一个类:

You should provide connection string to your context via :base(connectionString). Create a class as below:

public class ConnectionStringBuilder
{
    public static string Construct()
    {
        var newConnStringBuilder = new SqlConnectionStringBuilder
        {
            UserID = "user",
            Password = "pass",
            InitialCatalog = "databaseName",
            DataSource = "serverName"
        };

        var entityConnectionBuilder = new EntityConnectionStringBuilder
        {
            Provider = "System.Data.SqlClient",
            ProviderConnectionString = newConnStringBuilder.ToString(),
            Metadata = @"res://*/TestModel.csdl|
                            res://*/TestModel.ssdl|
                            res://*/TestModel.msl"
        };

        return entityConnectionBuilder.ToString();
    }
}

然后修改你的 Context 构造函数，如下所示:

Then modify your Context constructor to look like this:

public DbContext()
    : base(ConnectionStringBuilder.Construct())
{
}

现在应该可以正常工作了.(来源)

It should work fine now. (source)

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