C# – The type or namespace name ‘Entity’ does not exist in the namespace ‘System.Data’

.netasp.netc++entity-framework-4.1web-services

I'm using WS class and it gave me error when I run the application:

The type or namespace name 'Entity' does not exist in the namespace 'System.Data' 

I have a reference to the System.Data; and to System.Data.Entity;
But no changes. I keep getting the error. I have also in the web.config the line:

<compilation debug ="true" targetFramework="4.0"/>

Best Solution

Right-click on the Solution from the Visual Studio Solution Explorer click the Manage Nuget packages for solution and install the EntityFramework