.NET 3.5 - DLINQ(LINQ to SQL)之面向對象的添加、查詢、更新和刪除

步步為營VS 2008 + .NET 3.5(8) - DLINQ(LINQ to SQL)之面向對象的添加、查詢、更新和刪除

作者：webabcd


介紹
以Northwind為示例數據庫，DLINQ(LINQ to SQL)之完全面向對象的添加操作、查詢操作、更新操作和刪除操作


示例
Sample.aspx

<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Sample.aspx.cs"
????????Inherits="LINQ_DLINQ_Sample" Title="面向對象的添加、查詢、更新和刪除" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
????????<p>
????????????????分類名稱：<asp:TextBox ID="txtCategoryName" runat="server"></asp:TextBox>
?????????????????? 分類描述：<asp:TextBox ID="txtDescription" runat="server"></asp:TextBox>
??????????????????
????????????????<asp:Button ID="btnAdd" runat="server" Text="添加" OnClick="btnAdd_Click" />
????????</p>
????????<asp:GridView ID="gvCategory" runat="server" DataKeyNames="CategoryID" OnSelectedIndexChanged="gvCategory_SelectedIndexChanged"
????????????????OnRowDeleting="gvCategory_RowDeleting" OnRowCancelingEdit="gvCategory_RowCancelingEdit"
????????????????OnRowEditing="gvCategory_RowEditing" OnRowUpdating="gvCategory_RowUpdating">
????????????????<Columns>
????????????????????????<asp:CommandField ShowSelectButton="True" ShowEditButton="True" ShowDeleteButton="True">
????????????????????????</asp:CommandField>
????????????????</Columns>
????????</asp:GridView>
????????<br />
????????<asp:DetailsView ID="dvProduct" runat="server" DataKeyNames="ProductID">
????????</asp:DetailsView>
</asp:Content>

Sample.aspx.cs

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;

using DAL;

public partial class LINQ_DLINQ_Sample : System.Web.UI.Page
{
????????// 實例化一個NorthwindDataContext（DataContext）
????????NorthwindDataContext _ctx = new NorthwindDataContext();

????????protected void Page_Load(object sender, EventArgs e)
????????{
????????????????if (!Page.IsPostBack)
????????????????{
????????????????????????BindCategory();
????????????????}
????????}

????????private void BindCategory()
????????{
????????????????// NorthwindDataContext對象的Category屬性就是Category集合
????????????????var categories = _ctx.Categories;

????????????????gvCategory.DataSource = categories;
????????????????gvCategory.DataBind();
????????}

????????protected void btnAdd_Click(object sender, EventArgs e)
????????{
????????????????// 實例化一個Category
????????????????Categories c = new Categories();

????????????????// 設置Category對象的相關屬性
????????????????c.CategoryName = txtCategoryName.Text;
????????????????c.Description = txtDescription.Text;

????????????????// 使用NorthwindDataContext對象的InsertOnSubmit()方法添加Category對象
????????????????_ctx.Categories.InsertOnSubmit(c);

????????????????// 生成并執行相應的SQL命令
????????????????_ctx.SubmitChanges();

????????????????gvCategory.EditIndex = -1;
????????????????BindCategory();
????????}

????????protected void gvCategory_SelectedIndexChanged(object sender, EventArgs e)
????????{
????????????????// 使用查詢語法獲得Product集合
????????????????var products = from p in _ctx.Products
???????????????????????????????????????????? where p.Categories.CategoryID == (int)gvCategory.SelectedValue
???????????????????????????????????????????? select p;

????????????????dvProduct.DataSource = products;
????????????????dvProduct.DataBind();
????????}

????????protected void gvCategory_RowDeleting(object sender, GridViewDeleteEventArgs e)
????????{
????????????????// 使用Single查詢操作符獲取指定的Category對象
????????????????Categories category = _ctx.Categories.Single(c => c.CategoryID == (int)gvCategory.DataKeys[e.RowIndex].Value);

????????????????// 使用DeleteOnSubmit()方法刪除NorthwindDataContext對象的Category集合中的指定Category對象
????????????????_ctx.Categories.DeleteOnSubmit(category);

????????????????// 生成并執行相應的SQL命令
????????????????_ctx.SubmitChanges();

????????????????gvCategory.EditIndex = -1;
????????????????BindCategory();
????????}

????????protected void gvCategory_RowUpdating(object sender, GridViewUpdateEventArgs e)
????????{
????????????????// 使用查詢語法和Single查詢操作符獲取指定的Category對象
????????????????Categories category = (from c in _ctx.Categories
???????????????????????????????????????????????????????? where c.CategoryID == (int)gvCategory.DataKeys[e.RowIndex].Value
???????????????????????????????????????????????????????? select c).Single();

????????????????// 設置Category對象的相關屬性
????????????????category.CategoryName = ((TextBox)gvCategory.Rows[e.RowIndex].Cells[2].Controls[0]).Text;
????????????????category.Description = ((TextBox)gvCategory.Rows[e.RowIndex].Cells[3].Controls[0]).Text;

????????????????// 生成并執行相應的SQL命令
????????????????_ctx.SubmitChanges();

????????????????gvCategory.EditIndex = -1;
????????????????BindCategory();
????????}

????????protected void gvCategory_RowEditing(object sender, GridViewEditEventArgs e)
????????{
????????????????gvCategory.EditIndex = e.NewEditIndex;
????????????????BindCategory();
????????}

????????protected void gvCategory_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
????????{
????????????????gvCategory.EditIndex = -1;
????????????????BindCategory();
????????}
}

OK
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本文出自 “webabcd” 博客，請務必保留此出處http://webabcd.blog.51cto.com/1787395/345006