泛型处理ToEntity

　　　　 #region 泛型处理
        /// <summary>
        /// 实体对象赋值转换
        /// 参数实体必需包含无参构造函数，否则出错
        /// </summary>
        /// <typeparam name="T">实体对象</typeparam>
        /// <returns></returns>
        public static T CopyTo<T>(this T t)
        {
            Type type = typeof(T);
            T obj = (T)Activator.CreateInstance(type, null);
            foreach (PropertyInfo p in type.GetProperties())
            {
                dynamic tt = t.GetType().GetProperty(p.Name).GetValue(t, null);
                p.SetValue(obj, tt, null);
            }
            return obj;
        }
        #endregion
        #region DataTale
        /// <summary>
        /// 将DataTable转换成实体【DataTale中列数可以小于实体中列数】
        /// DataTabele中列名应与实体属性名一一对应
        /// </summary>
        /// <typeparam name="Entity">实体对象</typeparam>
        /// <param name="dt">数据DataTable</param>
        /// <returns>实体列表</returns>
        public static List<Entity> ToEntity<Entity>(this DataTable dt, bool IsDefault = false)
        {
            Type type = typeof(Entity);
            List<Entity> list = new List<Entity>();
            foreach (DataRow r in dt.Rows)
            {
                Entity obj = (Entity)Activator.CreateInstance(type, null);
                foreach (DataColumn c in dt.Columns)
                {
                    try
                    {
                        PropertyInfo p = type.GetProperty(c.ColumnName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
                        if (p == null)
                        {
                            continue;
                        }
                        object val = r[c.ColumnName];
                        if (val == DBNull.Value && IsDefault && p.PropertyType.Name.Contains("Nullable"))
                        {
                            string strType = p.PropertyType.ToString().Split('[')[1].Replace("]", "");
                            val = p.PropertyType.IsValueType ? Activator.CreateInstance(Type.GetType(strType)) : null;
                        }
                        int enumVal = 0;
                        if (p.PropertyType.IsEnum && int.TryParse(val.ToString(), out enumVal))
                        {//枚举赋值处理
                            val = Enum.ToObject(p.PropertyType, enumVal);
                        }
                        if (val == DBNull.Value && !p.PropertyType.Name.Contains("Nullable") && p.PropertyType.IsValueType)//不允许为空的值类型使用默认值
                        {
                            string strType = p.PropertyType.ToString().Replace("[", "").Replace("]", "");//得到类型名
                            val = Activator.CreateInstance(Type.GetType(strType));
                        }
                        p.SetValue(obj, Convert.ChangeType(val, p.PropertyType.Name.Contains("Nullable") ? Nullable.GetUnderlyingType(p.PropertyType) : p.PropertyType), null);
                    }
                    catch (Exception ex)
                    {
                        LogUtil.Log(ex.Message + ex.StackTrace + c.ColumnName, "Entity");
                    }
                }
                list.Add(obj);
            }
            return list;
        }

        /// <summary>
        /// 将DataTable转换成实体【DataTale中列数可以小于实体中列数】
        /// DataTabele中列名应与实体属性名一一对应
        /// </summary>
        /// <typeparam name="Entity">实体对象</typeparam>
        /// <param name="dt">数据DataTable</param>
        /// <returns>实体列表</returns>
        public static Entity Default<Entity>(this DataTable dt, bool IsDefault = false)
        {
            List<Entity> list = dt.ToEntity<Entity>(IsDefault);
            Entity en = default(Entity);
            if (list != null && list.Count > 0)
            {
                en = list[0];
            }
            return en;
        }
 
        public static DataTable ToDataTable<T>(this List<T> list, bool isStoreDB = true)
        {
            Type tp = typeof(T);
            PropertyInfo[] proInfos = tp.GetProperties();
            DataTable dt = new DataTable();
            foreach (var item in proInfos)
            {
                dt.Columns.Add(item.Name, item.PropertyType); //添加列明及对应类型
            }
            foreach (var item in list)
            { 
                DataRow dr = dt.NewRow();
                foreach (var proInfo in proInfos)
                { 
                    object obj = proInfo.GetValue(item,null);
                    if (obj == null)
                    {
                        continue;
                    } 
                    if (isStoreDB && proInfo.PropertyType == typeof(DateTime) && Convert.ToDateTime(obj) < Convert.ToDateTime("1753-01-01"))
                    {
                        continue;
                    } 
                    dr[proInfo.Name] = obj; 
                }
                dt.Rows.Add(dr);
            }
            return dt;
        }
 
        #endregion