Question

I use entity framework and have a set of users:

 public class DbModel : DbContext
 {
     public DbSet<User> Users { get; set; }

I add a User like so:

  User UserOne = new User();
  model.Users.Add( UserOne );

I request the users count:
int userCount = model.Users.Count();

userCount is “0” I would expect “1”. Adding DetectChanges doen’t help.
After “model.SaveChanges()” the Count = 1, but that is to late I need to combine the in memory stuff with the DB stuff for validation. Is there a way to do this?

SOLUTION

Using the answer of Erik Philips I wrote the following extension method for the DbSet

public static class DBSetExtentions
{
     public static IEnumerable<T> AllMembers<T>(
         this DbSet<T> target, 
         Func<T, bool> selection
         )  where T : class
    {
        return target.Local.Where(selection).Union(target.Where(selection));
    }
 }

it allows me to do selections an validations accross all entities like:

    private void ValidateEmail(ValidationDto validationDto)
    {

        int usersWithSameEmail =
            validationDto.Model.Users.AllMembers(
                x => x.EmailAddress.Equals( EmailAddress ) ).Count();

        if (usersWithSameEmail > 1)
        {
            validationDto.Result.Add(new ValidationResult("Email address is in use"));
        }
    }

Answer 1

You can query the client side of items (committed and uncomitted) to your data storage by using Local.

var count = model.Users.Local.Count();

One caveat is that this is only the local representation of Users. Meaning it could contain a partial amount of users from the database (changed and/or unchanged), and new users you’ve created and not saved.

Interesting Article – Using DbContext in EF 4.1 Part 7: Local Data