Cannot convert type System.Data.Entity.DbSet to System.Collections.Generic.ICollection

Question

I am using Entity Framework 4.1 code first in an MVC 3 app.

I have the following repository:

public class BankRepository : IBankRepository
{
     HefContext db = new HefContext();

     public ICollection<Bank> GetAll()
     {
          return db.Banks;
     }
}

I get an error when returning db.Banks. I'm not sure what it means, can someone please help clarify and how to change it so that the error goes away? The error is:

Cannot implicitly convert type 'System.Data.Entity.DbSet<MyProject.Core.DomainObjects.Bank>' to 'System.Collections.Generic.ICollection<MyProject.Core.DomainObjects.Bank>'. An explicit conversion exists (are you missing a cast?)

What is returned by db.Banks? An IEnumerable?

score 4 · Accepted Answer · edited Sep 28 '16 at 14:35

4

db.Banks is of type DbSet. This class does not implement ICollection interface. Change the return type of the method to IQueryable<Bank> or IEnumerable<Bank>.

public class BankRepository : IBankRepository
{
     HefContext db = new HefContext();

     public IQueryable<Bank> GetAll()
     {
          return db.Banks;
     }
}

edited Sep 28 '16 at 14:35

Gareth

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answered Nov 10 '11 at 06:33

Eranga

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Most of the examples online use ICollection? Why is this? – Brendan Vogt Nov 10 '11 at 06:44
@Brendan situation has to be different in those examples because your code does not compile. – Eranga Nov 10 '11 at 07:40

score 2 · Answer 2 · edited May 23 '17 at 11:45

2

ICollection is used only as the backing property to support LazyLoading, not as the result of a method. Check here ;)

edited May 23 '17 at 11:45

Community

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answered Nov 26 '11 at 17:35

tec-goblin

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Cannot convert type System.Data.Entity.DbSet to System.Collections.Generic.ICollection

2 Answers2