Question

I have a table where i have one property called ID_client where is primary key. I have to search the max value from this property and do +1 to assign to a new client. I have the following code..

public int IDuser()
    {

        MembershipUserCollection iduser = Membership.GetAllUsers();

        foreach (MembershipUser member in iduser)
        {

            UserEntity entity = new UserEntity();
            entity.Username = member.UserName;
            entity.Roles = "Users";
            entity.Email = member.Email;
            for (int i = 1; i <=iduser.Count; i++)
            {
                entity.ID_client = i;
            }
            _entities.Add(entity);

        }

        int maxID = _entities.Max(x => x.ID_client) +1;

        return maxID;

    }

If i create, for example, four users all be ok, 1, 2, 3 and 4. But if i delete third user, i have 1, 2 and 4 as ID_client, and the next new user, i want to assign 5, but this function returns me 4,not 5. Is like the function do a count + 1 instead max value +1.

Can someone help me?

Thanks.

Answer 1

The name you gave to your method does not reflect what the method is supposed to do. Give it a speaking name. I do not see what the inner loop is supposed to do. Drop it. Get the maximum id BEFORE adding new records. Maybe you want something like this

public int CopyMembershipUsersToUserEntities()
{
    int lastID = _entities.Max(x => x.ID_client); 
    foreach (MembershipUser member in Membership.GetAllUsers()) 
    { 
        UserEntity entity = new UserEntity(); 
        entity.Username = member.UserName; 
        entity.Roles = "Users"; 
        entity.Email = member.Email; 
        entity.ID_client = ++lastID; 
        _entities.Add(entity); 
    } 
    return lastID; 
} 

As others have already said, you could also use an auto increment column. This is safer in a multiuser environment.