C#;DataTable添加列;DataTable转List泛型集合;List泛型集合转DataTable泛型集合;

给DataTable添加列

 string sql = "select * from cgpmb order by code";
            DataTable dt = Bobole.Data.OracleDataRegester.GetListBySql(sql).Tables[];
            dt.Columns.Add("PCode", typeof(string));   　　//假如数据库查询出来的DataTable没有你想要的列   Remove("")可以删除列
            for (int i = ; i < dt.Rows.Count; i++)
            {
                try
                {
                    dt.Rows[i]["PCode"] = dt.Rows[i]["Code"].ToString().Remove(dt.Rows[i]["Code"].ToString().Length - , );
                }
                catch (Exception)
                {
                    dt.Rows[i]["PCode"] = "";
                }
            }

将DataTable转化为list泛型集合

        public static List<T> TableToList<T>(DataTable dt, bool isStoreDB = true)
        {
            List<T> list = new List<T>();
            Type type = typeof(T);
            //List<string> listColums = new List<string>();
            PropertyInfo[] pArray = type.GetProperties(); //集合属性数组
            foreach (DataRow row in dt.Rows)
            {
                T entity = Activator.CreateInstance<T>(); //新建对象实例
                foreach (PropertyInfo p in pArray)
                {
                    if (!dt.Columns.Contains(p.Name) || row[p.Name] == null || row[p.Name] == DBNull.Value)
                    {
                        continue;  //DataTable列中不存在集合属性或者字段内容为空则，跳出循环，进行下个循环
                    }
                    if (isStoreDB && p.PropertyType == typeof(DateTime) && Convert.ToDateTime(row[p.Name]) < Convert.ToDateTime("1753-01-01"))
                    {
                        continue;
                    }
                    try
                    {
                        var obj = Convert.ChangeType(row[p.Name], p.PropertyType);//类型强转，将table字段类型转为集合字段类型
                        p.SetValue(entity, obj, null);
                    }
                    catch (Exception)
                    {
                        // throw;
                    }
                }
                list.Add(entity);
            }
            return list;
        }

将list泛型集合转化为DataTable

        /// <summary>
        /// 转化一个DataTable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        private static System.Data.DataTable ToDataTable<T>(IEnumerable<T> list)
        {
            //创建属性的集合
            List<PropertyInfo> pList = new List<PropertyInfo>();
            //获得反射的入口
            Type type = typeof(T);
            System.Data.DataTable dt = new System.Data.DataTable();
            //把所有的public属性加入到集合 并添加DataTable的列
            Array.ForEach<PropertyInfo>(type.GetProperties(), p => { pList.Add(p); dt.Columns.Add(p.Name, p.PropertyType); });
            foreach (var item in list)
            {
                //创建一个DataRow实例
                DataRow row = dt.NewRow();
                //给row 赋值
                pList.ForEach(p => row[p.Name] = p.GetValue(item, null));
                //加入到DataTable
                dt.Rows.Add(row);
            }
            return dt;
        }