.NET 3.5(12) - DLINQ(LINQ to SQL)之事务处理和并发处理

步步为营VS 2008 + .NET 3.5(12) - DLINQ(LINQ to SQL)之事务处理和并发处理

作者：webabcd


介绍
以Northwind为示例数据库，DLINQ(LINQ to SQL)之事务处理和并发处理


示例
TransactionAndConcurrency.aspx

<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="TransactionAndConcurrency.aspx.cs"
        Inherits="LINQ_DLINQ_TransactionAndConcurrency" Title="事务处理和并发处理" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
        事务处理和并发处理详见：TransactionAndConcurrency.aspx.cs
</asp:Content>

 

TransactionAndConcurrency.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;
using System.Transactions;

public partial class LINQ_DLINQ_TransactionAndConcurrency : System.Web.UI.Page
{
        protected void Page_Load(object sender, EventArgs e)
        {
                // 事务处理（DataContext.SubmitChanges()会做默认的事务处理）
                TransactionDemo1();

                // 事务处理（用DataContext.Connection.BeginTransaction()的方式做事务处理）
                TransactionDemo2();

                // 事务处理
                TransactionDemo3();

                // 并发处理
                Concurrency();
        }

        /// <summary>
        /// 事务处理（DataContext.SubmitChanges()会做默认的事务处理）
        /// </summary>
        private void TransactionDemo1()
        {
                try
                {
                        NorthwindDataContext ctx = new NorthwindDataContext();

                        ctx.Categories.InsertOnSubmit(new Categories { CategoryName = "test", Description = "test" });
                        ctx.Categories.InsertOnSubmit(new Categories { CategoryID = 1 });

                        ctx.SubmitChanges();
                }
                catch
                { }
        }

        /// <summary>
        /// 事务处理（用DataContext.Connection.BeginTransaction()的方式做事务处理）
        /// </summary>
        private void TransactionDemo2()
        {
                int? categoryId = null;

                NorthwindDataContext ctx = new NorthwindDataContext();

                if (ctx.Connection.State != ConnectionState.Open)
                {
                        ctx.Connection.Open();
                }

                System.Data.Common.DbTransaction tran = ctx.Connection.BeginTransaction();
                ctx.Transaction = tran;

                try
                {
                        ctx.AddCategory("test", "test", ref categoryId);
                        ctx.DeleteCategory(1);

                        tran.Commit();
                }
                catch
                {
                        tran.Rollback();
                }
        }

        /// <summary>
        /// 事务处理（用System.Transactions.TransactionScope做事务处理）
        /// </summary>
        private void TransactionDemo3()
        {
                int? categoryId = null;

                using (TransactionScope tc = new TransactionScope())
                {
                        try
                        {
                                NorthwindDataContext ctx = new NorthwindDataContext();
                                
                                ctx.AddCategory("test", "test", ref categoryId);
                                ctx.DeleteCategory(1);

                                tc.Complete();
                        }
                        catch
                        { }
                }
        }

        /// <summary>
        /// 并发处理
        /// </summary>
        private void Concurrency()
        {
                // 修改字段的UpdateCheck为Never，可在对象关系设计器（Object Relational Designer）中修改
                // [Column(Storage="_UnitPrice", DbType="Money")]
                // [Column(Storage="_UnitPrice", DbType="Money", UpdateCheck=UpdateCheck.Never)]

                NorthwindDataContext ctx = new NorthwindDataContext();

                var products = ctx.Products;

                foreach (var p in products)
                {
                        p.UnitPrice ++;
                }

                try
                {
                        // 表示即使发生冲突也要继续
                        ctx.SubmitChanges(System.Data.Linq.ConflictMode.ContinueOnConflict);
                }
                catch (System.Data.Linq.ChangeConflictException e)
                {
                        foreach (System.Data.Linq.ObjectChangeConflict occ in ctx.ChangeConflicts)
                        {
                                Products p = (Products)occ.Object;

                                // 以当前客户端中的值为准
                                occ.Resolve(System.Data.Linq.RefreshMode.OverwriteCurrentValues);

                                // 以当前数据库中的值为准
                                occ.Resolve(System.Data.Linq.RefreshMode.KeepCurrentValues);

                                // 如果数据库中的值没有发生变化，则以当前客户端中的值为准。否则，则以当前数据库中的值为准
                                occ.Resolve(System.Data.Linq.RefreshMode.KeepChanges);

                                foreach (System.Data.Linq.MemberChangeConflict mcc in occ.MemberConflicts)
                                {
                                        // 当前客户端中的值
                                        string currentValue = mcc.CurrentValue.ToString();
                                        
                                        // 原来数据库中的值
                                        string originalValue = mcc.OriginalValue.ToString();
                                        
                                        // 当前数据库中的值
                                        string databaseValue = mcc.DatabaseValue.ToString();

                                        // 以当前客户端中的值为准
                                        mcc.Resolve(System.Data.Linq.RefreshMode.OverwriteCurrentValues);

                                        // 以当前数据库中的值为准
                                        mcc.Resolve(System.Data.Linq.RefreshMode.KeepCurrentValues);
                                        
                                        // 如果数据库中的值没有发生变化，则以当前客户端中的值为准。否则，则以当前数据库中的值为准
                                        mcc.Resolve(System.Data.Linq.RefreshMode.KeepChanges);
                                }
                        }

                }

                // 表示只要发生冲突就不再继续
                ctx.SubmitChanges(System.Data.Linq.ConflictMode.FailOnFirstConflict);    
                
                // ctx.SubmitChanges();
        }
}

 

OK
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本文出自 “webabcd” 博客，请务必保留此出处http://webabcd.blog.51cto.com/1787395/345015