asp.net MVC3 LINQ expression

Question

I have used to create a custom role provider.

My Project - asp.net MVC3, Entity Framework 4

There is a problem with the GetRolesForUser method.

Custom RoleProvider - GetRolesForUser Method

    // The user to return a list of roles for.
    public override string[] GetRolesForUser(string userAccount)
    {
        var userId = userRepository.GetUser(userAccount).UserId;

        var roleIds = from ur in usersInRoleRepository.UsersInRoles
                    where ur.UserId == userId
                    select ur.RoleId;

        var roleNames = from r in roleRepository.Roles
                        where roleIds.Contains(r.RoleId)
                        select r.RoleName;


        if (roleNames != null)
        {
            **return roleNames.ToArray();  // here Error**
        }
        else
        {
            return new string[0];
        }
    }

Error Message : The specified LINQ expression contains references to queries that are associated with different contexts.

I do not know whether there is something wrong with this code.

Please Help.

User Entity

public class User
{
    public Guid UserId { get; set; }
    public string UserAccount { get; set; }
    public string Password { get; set; }
    public string UserEmail { get; set; }
    public DateTime JoinDate { get; set; }
    public DateTime LoginDate { get; set; }
}

Role Entity

public class Role
{
    public Guid RoleId { get; set; }
    public string RoleName { get; set; }
    public DateTime CreateDate { get; set; }
}

UsersInRole Entity

public class UsersInRole
{
    public Guid UserId { get; set; }
    public Guid RoleId { get; set; }
    public DateTime SetDate { get; set; }
}

Answer 1

You cant make queries that are associated with different contexts in single query. Try to change your roleIds linq code to avoide it's lazy loading by converting it to array:

var roleIds = (from ur in usersInRoleRepository.UsersInRoles
              where ur.UserId == userId
              select ur.RoleId).ToArray();