I am trying to use ADO.Net Codefirst feature of latest Entity Framework 4.0. As part of that I have installed Entity Framework CTP 4 from Microsft and using Scott's tutorial to create the model first. Inside the tutorial DBContext and DBSet<> is specified. Could some tell what is the reference to be used in order to access this class.
I have used the following references however nothing happens for DBContext and DBSet<>
- System.Data.Entity
- System.Data.Entity.Design
Use CTP5 instead it is newer version with some changes in API. You have to add reference to EntityFramework.dll which is installed in CTP directory - default is: c:\Program Files\Microsoft ADO.NET Entity Framework Feature CTP5\Binaries\EntityFramework.dll for 32bit system. On 64bit system it will be placed in Program Files (x86).
You can use the Library Package Manager if you have it (it installs automatically with MVC 3.0).
From within your project in Visual Studio 2010, go to
Tools > Library Package Manager > Package Manager Console
From within your project in Visual Studio 2013, go to
Tools > NuGet Package Manager > Package Manager Console
In the console, after the PM> prompt, type
install-package entityframework
This will install the package and add the EntityFramework reference to your project.
Use "DbContext" vs "DBContext", and "DbSet" vs "DBSet". The case sensitivity is the issue.
To add EF to your project use the Package Manager Console and issue the command:
Install-Package EntityFramework
You shouldn't link directly to the DLLs' installed location as mentioned in another answer.
The blogpost mentions the assembly:
The DbContext and DbSet classes used above are provided as part of the EF4 Code-First library. You’ll need to add a reference to the System.Data.Entity.CTP assembly that is installed into the \Program Files\Microsoft ADO.NET Entity Framework Feature CTP4\Binaries directory to reference these classes. You’ll also want to add a “using System.Data.Entity” namespace statement at the top of your “NerdDinners” class file.
However I do believe the new CTP5 includes some changes to codefirst, so I would suggest to take a look at that one instead.
I was following the MvcMusicStore Tutorial (using Mvc 4 instead of Mvc 3).
I found in Part 4 I was having issues with this (http://www.asp.net/mvc/tutorials/mvc-music-store/mvc-music-store-part-4).
When I added the following reference using System.Data.Entity;, I got the following error:
the type or namespace name 'entity' does not exist in the namespace 'system.data'
@Fecklmore's solution worked for me.
Open the Package Manager Console by going to Tools > Library Package Manager > Package Manager Console.
Then type in the following: Install-Package EntityFramework
This will install EntityFramework (i.e. EF) into your project, and will eliminate the error above.
if you are using .NET 3.5 then change your target framework to .NET 4.0
来源：https://stackoverflow.com/questions/4898742/references-for-dbcontext-dbset-in-entity-framework