对比Model前后数据保存不同值

1.示例代码
 public class SysLogBLL<T,W> : BLLBase where T : new()
    {
        #region   比较方法
         /// <summary>
         /// 复制对象到指定对象中 只复制名称一样的
         /// </summary>
         /// <param name="obj"></param>
         /// <returns></returns>
        public T Clone(W obj)
        {
            Type objTye = typeof(T);
            Type objTyeW = typeof(W);
            T t = new T();
            PropertyInfo[] proinfos = objTye.GetProperties();
            PropertyInfo[] proinfosw = objTyeW.GetProperties();
            foreach (var i in proinfos)
            {
                foreach (var j in proinfosw)
                {
                    if (i.Name == j.Name)
                    {
                        object o = j.GetValue(obj, null);
                        if (i.GetSetMethod() != null)
                        {
                            i.SetValue(t, o, null);
                        }
                    }
                }
            }
            return t;
        }
        public T Clone(T obj)
        {
            Type objTye = typeof(T);
            T model = new T();

            PropertyInfo[] properties = objTye.GetProperties();
            foreach (PropertyInfo property in properties)
            {
                if (!property.IsSpecialName)
                {
                    object o = property.GetValue(obj, null);
                    if (property.GetSetMethod() != null)
                    {
                        property.SetValue(model, o, null);
                    }
                }
            }
            return model;
        }
        private bool IsEqual(Type dataType, object oldObj, object newObj)
        {
            if (oldObj == null && newObj == null) return true;
            if (oldObj != null && newObj != null)
            {
                if (dataType == typeof(int)) return (int)oldObj == (int)newObj;
                if (dataType == typeof(decimal)) return (decimal)oldObj == (decimal)newObj;
                if (dataType == typeof(double)) return (double)oldObj == (double)newObj;
                if (dataType == typeof(Guid)) return (Guid)oldObj == (Guid)newObj;
                if (dataType == typeof(DateTime)) return (DateTime)oldObj == (DateTime)newObj;
                if (dataType == typeof(string)) return (string)oldObj == (string)newObj;
                return true; //return oldObj.Equals(newObj);
            }
            else
            {
                if (dataType.BaseType == typeof(object)) return true;
                else return false;
            }
        }

        /// <summary>
        /// 比较两个实体，然后返回实体中每个属性值不同的内容
        /// </summary>
        /// <param name="oldObj"></param>
        /// <param name="newObj"></param>
        /// <returns></returns>
        public List<Hashtable> Compare(T oldObj, T newObj)
        {
            Type objTye = typeof(T);
            List<Hashtable> list = new List<Hashtable>();
            // FieldInfo[] myFields = objTye.GetFields(BindingFlags.Public | BindingFlags.Instance);
            PropertyInfo[] proinfos = objTye.GetProperties();

            try
            {
                foreach (var item in proinfos)
                {
                    object o = item.GetValue(oldObj, null);
                    object n = item.GetValue(newObj, null);
                    var itype = item.PropertyType.GetGenericArguments();
                    Type itemtype = itype.Length >  ? itype[] : item.PropertyType;
                    if (!IsEqual(itemtype, o, n))
                    {
                        Hashtable hs = new Hashtable();
                        hs.Add("Key", item.Name);
                        hs.Add("KeyType", (itemtype != null ? itemtype.Name : item.PropertyType.Name));
                        hs.Add("oValue", o);
                        hs.Add("nValue", n);
                        list.Add(hs);
                    }
                }
            }
            catch (Exception ex)
            {

                throw;
            }

            return list;
        }

        #endregion

        #region 保存LogAction
        /// <summary>
        /// 保存数据
        /// </summary>
        /// <param name="Lgaction">Crm_LogAction 对象</param>
        /// <param name="originaldata">原始对象数据</param>
        /// <param name="currentdata">当前对象数据</param>
        /// <returns></returns>
        public bool SaveLogActoin(Crm_LogAction Lgaction, T originaldata, T currentdata)
        {
            bool result = false; //执行结果
            if (Lgaction != null)
            {
                try
                {
                    MainEntities.Crm_LogAction.Add(Lgaction);
                    MainEntities.SaveChanges();
                    List<Hashtable> lt = Compare(originaldata, currentdata);

if (lt.Count() > )
                    {
                        foreach (var h in lt)
                        {
                            Hashtable hitem = h as Hashtable;
                            if (hitem != null && hitem.Count > )
                            {
                                MainEntities.Crm_LogActionDetail.Add(new Crm_LogActionDetail
                                {
                                    LogId = Lgaction.LogId,
                                    ColumnName = hitem["Key"].ToString(),
                                    ColumnDataType = hitem["KeyType"].ToString(),
                                    CreateTime = DateTime.Now,
                                    CreateUser = CurrentUser.Name + "[" + CurrentUser.Id + "]",
                                    NewValue = hitem["nValue"].ToString(),
                                    OldValue = hitem["oValue"].ToString(),
                                });
                            }
                        }
                        MainEntities.SaveChanges();
                        result = true;
                    }
                }
                catch (Exception)
                {

                    result = false;
                }
            }
            return result;
        }

        /// <summary>
        ///  保存数据
        /// </summary>
        /// <param name="TableName">表名</param>
        /// <param name="OperationId">操作类型 0=add  1=delte  2=update </param>
        /// <param name="originaldata"></param>
        /// <param name="currentdata"></param>
        /// <returns></returns>
        public bool SaveLogActoin(string TableName, int OperationId, T originaldata, T currentdata)
        {
            bool result = false; //执行结果

               Crm_LogAction Lgaction=new Crm_LogAction ();
                try
                {
                    var query = MainEntities.Crm_LogActionType.Where(w => w.TableName == TableName).SingleOrDefault();
                     if (query != null)
                     {
                         Lgaction=   new Crm_LogAction
                            {
                                OperationId = OperationId,//修改=2
                                CreateTime = DateTime.Now,
                                CreateUser = CurrentUser.Name + "[" + CurrentUser.Id + "]",
                                LogTypeId = query.TypeId,
                                TableName = query.TableName,
                                BusinessName = query.BusinessName
                            };

                       MainEntities.Crm_LogAction.Add(Lgaction);
                       MainEntities.SaveChanges();

                      List<Hashtable> lt = Compare(originaldata, currentdata);if (lt.Count() > )
                       {
                           foreach (var h in lt)
                           {
                               Hashtable hitem = h as Hashtable;
                               if (hitem != null && hitem.Count > )
                               {
                                   MainEntities.Crm_LogActionDetail.Add(new Crm_LogActionDetail
                                   {
                                       LogId = Lgaction.LogId,
                                       ColumnName = hitem["Key"].ToString(),
                                       ColumnDataType = hitem["KeyType"].ToString(),
                                       CreateTime = DateTime.Now,
                                       CreateUser = CurrentUser.Name + "[" + CurrentUser.Id + "]",
                                       NewValue =hitem["nValue"]==null?"": hitem["nValue"].ToString(),
                                       OldValue =hitem["oValue"]==null?"": hitem["oValue"].ToString(),
                                   });
                               }
                           }
                           MainEntities.SaveChanges();
                           result = true;
                       }
                     }

                }
                catch (Exception)
                {

                    result = false;
                }
            return result;
        }
        #endregion
    }

2.调用示例：

SysLogBLL<Crm_Contact, ContactBankCreateOrEdit> Syslog = new SysLogBLL<Crm_Contact, ContactBankCreateOrEdit>();
Crm_Contact currentdata = Syslog.Clone(model); //新数据
Crm_Contact originaldata = dModel;

Syslog.SaveLogActoin("Crm_Contact", 2, originaldata, currentdata);