Question

class UserClass{

    #region Class properties which are binding from DB
    .
    .
    .
    #endregion


    #region Constructor Methods
    public UserClass(int _iUser_id)
    {
        // of course this is wrong but how can i quickly set properties 
        // which are coming from DB by extension method over context class?
        this = DAO.context.GetById<UserClass>(_iUser_id);
    }
    #endregion
}

Answer 1

You could use a static method instead of a constructor:

public static UserClass GetById(int userId) {
    return DAO.context.GetById<UserClass>(userId);
}