处理实体框架中的异常4

Question

我需要一种方法来区分使用实体框架LINQ的SQL异常,例如,当我从DbUpdateException获得的是大量嵌套的内部异常和无用的长错误消息时,如何区分出现外键约束违规或唯一约束违规？是否存在任何较低级别的异常,我可以执行类似"Catch FKException"的操作; 捕获"uniqueException"或类似的东西.

Answer 1

            try
            {
                //code
            }
            catch (System.Data.Entity.Validation.DbEntityValidationException e)
            {
                string rs = "";
                foreach (var eve in e.EntityValidationErrors)
                {
                    rs = string.Format("Entity of type \"{0}\" in state \"{1}\" has the following validation errors:", eve.Entry.Entity.GetType().Name, eve.Entry.State);
                    Console.WriteLine(rs);

                    foreach (var ve in eve.ValidationErrors)
                    {
                        rs += "<br />" + string.Format("- Property: \"{0}\", Error: \"{1}\"", ve.PropertyName, ve.ErrorMessage);
                    }
                }
                throw new Exception(rs);
            }

Answer 2

使用sql错误代码......

catch (DbUpdateException ex)
                    {
                        var sqlex = ex.InnerException.InnerException as SqlException;

                        if (sqlex != null)
                        {
                            switch (sqlex.Number)
                            {
                                case 547: throw new ExNoExisteUsuario("No existe usuario destino."); //FK exception
                                case 2627:
                                case 2601:
                                    throw new ExYaExisteConexion("Ya existe la conexion."); //primary key exception

                                default: throw sqlex; //otra excepcion que no controlo.


                            }
                        }

                        throw ex;
                    }