Could not find an implementation of the query pattern for source type 'System.Data.Entity.DbSet'

Question

I'm using Entity Framework for the first time, but it seems not working as expected.

I have this code:

using System; using System.Collections.Generic; using System.Data.Entity; using System.Linq;  public static class QueryClass {     public static void Query()     {         using (var context = new MyDbEntities())         {             DbSet<MyTable> set = context.Tables;             var query = from val in set select value;           }     } } 

On the query line (exactly the "set" variable is underlined in red) I get the error:

Could not find an implementation of the query pattern for source type 'System.Data.Entity.DbSet'.'Select' not found. Missing a reference or an using directive for 'System.Linq'

MyDbEntities is auto-generated by Entity Framework in a Database-First approach, context.Tables is a DbSet, so it should be able to use Linq, which has been added through the using directive. In order to avoid misurderstantings, within this class I find the following:

public virtual DbSet<MyTable> Tables { get; set; } 

What am I missing in order to make the select work?

Thank you.

Answer 1

you will need to add reference to System.Data.Linq

System.Data.Linq is LINQ-SQL specific (DataContext, etc)

using System; using System.Collections.Generic; using System.Data.Entity; using System.Data.Linq; using System.Linq;  public static class QueryClass {     public static void Query()     {         using (var context = new MyDbEntities())         {              IQueryable<MyTable> qTable= from t in context.Tables                                         select t; // can you confirm if your context has Tables or MyTables?             Console.WriteLine("Table Names:");             foreach (var t in qTable)             {                 Console.WriteLine(t.Name);//put the relevant property instead of Name             }         }      } }