实体框架 6：上下文在 Code First 模式下与从 EDMX 文件生成的代码一起使用

Question

I'm creating WPF application using Entity Framework 6 with database first approach. EF did everything for me and i'm able to connect to the database and so far downloading data works, so connection exists. But every time i add user control it gives me new error that connection string was not detected. Program works fine anyway, but its hard to program when your error window is flooded with it.

I have found out that changing context from:

public MediaRentalEntities()
     : base("name=MediaRentalEntities")
{
}

To this:

public MediaRentalEntities()
     : base("MediaRentalEntities")
{
}

Should fix the issue, but it doesn't. Now it throws exception (and shows this error multiple times, based how many user controls i have, currently 3):

The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development. This will not work correctly. To fix this problem do not remove the line of code that throws this exception. If you wish to use Database First or Model First, then make sure that the Entity Framework connection string is included in the app.config or web.config of the start-up project. If you are creating your own DbConnection, then make sure that it is an EntityConnection and not some other type of DbConnection, and that you pass it to one of the base DbContext constructors that take a DbConnection. To learn more about Code First, Database First, and Model First see the Entity Framework documentation here: http://go.microsoft.com/fwlink/?LinkId=394715

This is my current app.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
  </startup>
  <entityFramework>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <connectionStrings>
    <add name="MediaRentalEntities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;data source=localhost;initial catalog=MediaRental;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework" providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

It's starting to be tiring, i'm tempted to change to EntityFrameworkCore or even Dapper, it feels like EntityFramework6 is against the user, but WPF has way more functionality on .NET Framework.

Answer 1

in connection string replace MyModel with " MediaRentalEntities ".It will work

Or

If you have generated it using DB first then you will already have context class where code is like

 public MyModel()
     : base("name=MyModel")
{
}