LINQ to SQL 操作單一表格的Table類

前面介紹了DataContext類，它可以用來映射和串連資料庫，執行SQL命令，跟蹤實體物件的狀態。

下面介紹Table<TEntity>表示表格記錄，它是一個泛型集合類，它的元素就是表格實體物件。它提供一組方法，對元素進行添加刪除操作，並可以通過DataContext將這些操作儲存到資料庫。

表還是前面的那張表，在項目中添加了一個LINQ to SQL類。重點是InsertOnSubmit、DeleteOnSubmit等方法。

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace LINQ_to_SQL_Table{    /// <summary>    /// 操作單一表格的Table<TEntity>類    /// </summary>    class Program    {        static void Main(string[] args)        {            //1.a.Attach附加實體            DataClasses1DataContext dc1 = new DataClasses1DataContext();            tb_GuestInfo guset = new tb_GuestInfo() { Id=1, Name = "DebugLZQ", Age = 35, Tel = "138****8888" };            dc1.tb_GuestInfo.Attach(guset);//這樣的Attach僅僅附加實體，資料庫沒有更新            dc1.SubmitChanges();            //顯示附加成功            foreach (var g in dc1.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("---------");            //顯示資料庫沒有更新            DataClasses1DataContext dc2 = new DataClasses1DataContext();            foreach (var g in dc2.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("------------------------");            Console.ReadKey();            //2.InsertOnSubmit            dc2.tb_GuestInfo.InsertOnSubmit(guset);            dc2.SubmitChanges();            foreach (var g in dc2.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("------------------------");            Console.ReadKey();            //2b.InsertAllOnSubmit 插入集合            List<tb_GuestInfo> lst = new List<tb_GuestInfo>()             {                new tb_GuestInfo(){ Name="AA", Age=25,Tel="133****3333"},                new tb_GuestInfo(){ Name="BB", Age=25,Tel="135****5555"}            };            dc2.tb_GuestInfo.InsertAllOnSubmit(lst);            dc2.SubmitChanges();            foreach (var g in dc2.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("------------------------");            Console.ReadKey();            //            //3.DeleteOnSubmit            tb_GuestInfo entity = (from g in dc2.tb_GuestInfo                                   where g.Name == "AA"                                   select g).Single();            dc2.tb_GuestInfo.DeleteOnSubmit(entity);//            dc2.SubmitChanges();            foreach (var g in dc2.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("------------------------");            Console.ReadKey();            //3b.DeleteAllOnSubmit            IEnumerable<tb_GuestInfo> entitys = from g in dc2.tb_GuestInfo                                                where g.Name == "AA" || g.Name == "BB"                                                select g;            dc2.tb_GuestInfo.DeleteAllOnSubmit(entitys);            dc2.SubmitChanges();            foreach (var g in dc2.tb_GuestInfo)            {                Console.WriteLine("{0} {1} {2} {3}", g.Id, g.Name, g.Age, g.Tel);            }            Console.WriteLine("------------------------");            Console.ReadKey();                               }    }}

程式運行結果如下：