数据字典生成工具之旅(9)：多线程使用及介绍

这一篇将在之前的代码生成器上讲解多线程的应用，多线程的概念和好处这里就不多说了，另外从本篇开始后面的实例代码都将放到淘宝的SVN管理工具上维护，大家可以直接使用SVN工具进行下载。好了下面进入本篇内容。

阅读目录

线程的应用
winform程序中的多线程
本章总结
工具源代码下载
学习使用

线程的应用

这里先讲一下线程在Web程序中的一个应用，之前的那一版代码生成器没有考虑表数量多的情形，这里先模拟一下在数据库中创建300张表的情形，下面给出创建表的语句。

--模拟创建300张表，@IsDropTable=0 表示创建表 IsDropTable=1 表示删除创建的模拟表DECLARE @IsDropTable AS BITDECLARE @total AS INT DECLARE @i AS INTSELECT @i=1,@total=300,@IsDropTable=0WHILE @i<=@totalBEGINDECLARE @strSQL AS VARCHAR(1000)    --创建表    SELECT @strSQL='        CREATE TABLE myTest'+CONVERT(VARCHAR,@i)+'        (            [UserGUID] [uniqueidentifier] NOT NULL        )        EXEC sp_addextendedproperty N''MS_Description'', N''用户表'', ''SCHEMA'', N''dbo'', ''TABLE'', N''myTest'+CONVERT(VARCHAR,@i)+''', NULL, NULL        EXEC sp_addextendedproperty N''MS_Description'', N''用户GUID'', ''SCHEMA'', N''dbo'', ''TABLE'', N''myTest'+CONVERT(VARCHAR,@i)+''', ''COLUMN'', N''UserGUID''    '        IF @IsDropTable=1    BEGIN        --删除表        SELECT @strSQL='DROP TABLE myTest'+CONVERT(VARCHAR,@i)    END        EXEC(@strSQL)    SELECT @i=@i+1END

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我们来看下执行时间，差不多用了22秒，时间还是挺长的。可以将代码改造一下，使用多线程来生成代码。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Web;using System.Configuration;using System.Collections;using System.IO;using System.Data;using System.Threading;namespace Mysoft.Code.Services{    /// <summary>    /// 代码生成类    /// </summary>    public class CodeGenerator    {        //模版文件路径        private static string tmpPath = HttpContext.Current.Server.MapPath("/实体模版/Entity.vm");        //模版输出路径        private static string outPutPath = HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["outputPath"]);        private static readonly int Number10 = 400;        private static readonly int MaxThreadCount = 4;        /// <summary>        /// 批量生成代码        /// </summary>        /// <param name="args">模版文件参数</param>        public static void BatchGenerator(List<Hashtable> args)        {            if (!Directory.Exists(outPutPath))            {                Directory.CreateDirectory(outPutPath);            }            //生成文件数量<Number10，则不开启线程生成            if (args.Count < Number10)            {                DoWork(args);            }            else            {                //计算需要的线程数                int threadCount = args.Count % Number10 == 0 ? args.Count / Number10 : args.Count / Number10 + 1;                if (threadCount > MaxThreadCount)                {                    threadCount = MaxThreadCount;                }                //每个线程需要生成的实体数量                int threadPqgeSize = (args.Count / threadCount) + 1;                int total = 0;                //为每个线程准备参数                List<List<Hashtable>> threadParams = new List<List<Hashtable>>();                for (int i = 0; i < threadCount; i++)                {                    threadParams.Add(args.Skip(total).Take(threadPqgeSize).ToList());                    total += threadParams[i].Count;                }                //创建线程                List<Thread> threads = new List<Thread>();                for (int i = 1; i < threadCount; i++)                {                    Thread thread = new Thread(DoWork);                    thread.IsBackground = true;                    thread.Name = "CodeGenerator #" + i.ToString();                    threads.Add(thread);                    thread.Start(threadParams[i]);                }                // 为当前线程指派生成任务。                DoWork(threadParams[0]);                // 等待所有的编译线程执行线束。                foreach (Thread thread in threads)                {                    thread.Join();                }            }        }        private static void DoWork(Object listArgs)        {            List<Hashtable> list = (List<Hashtable>)listArgs;            foreach (Hashtable ht in list)            {                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, ((DataTable)ht["T"]).Rows[0]["table_name"].ToString()));            }        }    }}

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代码思路，判断要生成的实体数量和Number10的关系，然后计算所需的线程数。

关键的一点是 thread.Join()，这段是主线程等待每个线程执行完成。现在再来看下执行时间，差不多用了13秒，节省了将近10S的时间。

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winform程序中的多线程

下面来考虑这样的一个场景，在生成了文件的时候马上在列表中提示实体生成完成，即进度提示的功能。我们来看下winform中的两种实现方式。

1.利用委托实现

先看一下普通线程实现方式，执行的时候会抛出如下异常。

   foreach (var key in query)            {                dv.RowFilter = "tableid=" + key.tableid;                DataTable dtTable = dv.ToTable();                Hashtable ht = new Hashtable();                ht["T"] = dtTable;                string tableName = dtTable.Rows[0]["table_name"].ToString();                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, tableName));                Thread thread = new Thread(BindMessage);                thread.IsBackground = true;                thread.Name = "BindMessage:" + key.tableid;                thread.Start(tableName);            }

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先看一下msdn的介绍：

访问 Windows 窗体控件本质上不是线程安全的。如果有两个或多个线程操作某一控件的状态，则可能会迫使该控件进入一种不一致的状态。还可能出现其他与线程相关的 bug，包括争用情况和死锁。确保以线程安全方式访问控件非常重要。

　　C#中禁止跨线程直接访问控件，InvokeRequired是为了解决这个问题而产生的，当一个控件的InvokeRequired属性值为真时，说明有一个创建它以外的线程想访问它。

于是改变了思路，新建线程用以执行耗时的生成代码操作，在每生成一个实体时，通知UI线程更新dataGridView，达到实时更新的效果,这样主线程也不会阻塞了。

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using Mysoft.Map.Extensions.DAL;using System.Collections;using Mysoft.Code.Services;using System.IO;using System.Threading;namespace ThreadWin{    public partial class MainForm : Form    {        //模版文件路径        private static string tmpPath = AppDomain.CurrentDomain.BaseDirectory + @"实体模版\Entity.vm";        //模版输出路径        private static string outPutPath = AppDomain.CurrentDomain.BaseDirectory + @"模版输出路径";        private DataTable dtInfo = new DataTable();        /// <summary>        /// 消息发送请求委托        /// </summary>        /// <param name="Msg">消息</param>        delegate void SetMessageCallBack(object Msg);        public MainForm()        {            InitializeComponent();            dtInfo.Columns.Add("TableName");            dtInfo.Columns.Add("Info");            dtInfo.Columns.Add("Time");            Control.CheckForIllegalCrossThreadCalls = false;        }        private void btn_OK_Click(object sender, EventArgs e)        {            dtInfo.Clear();                        if (!Directory.Exists(outPutPath))            {                Directory.CreateDirectory(outPutPath);            }            //1.耗时的操作放在新建线程里面执行            Thread thread = new Thread(GeneratorFile);            thread.IsBackground = true;            thread.Start();            //2.使用系统的线程池进行线程操作            //ThreadPool.QueueUserWorkItem(GeneratorFile);        }        /// <summary>        /// 这里进行耗时的生成代码操作        /// </summary>        private void GeneratorFile()        {            //循环生成实体，并且在列表上显示进度            DataTable dt = GetAllTableInfo();            DataView dv = dt.DefaultView;            var query = (from p in dt.AsEnumerable()                         group p by new { TableId = p.Field<int>("tableid"), TableName = p.Field<string>("table_name") } into q                         select new { TableId = q.Key.TableId, TableName = q.Key.TableName }                        );            foreach (var key in query)            {                dv.RowFilter = "tableid=" + key.TableId;                DataTable dtTable = dv.ToTable();                Hashtable ht = new Hashtable();                ht["T"] = dtTable;                string tableName = dtTable.Rows[0]["table_name"].ToString();                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, key.TableName));                //消息提示                DataRow dr = dtInfo.NewRow();                dr["TableName"] = tableName;                dr["Info"] = "生成成功";                dr["Time"] = DateTime.Now.ToString();                dtInfo.Rows.Add(dr);                DataView dvOrder = dtInfo.DefaultView;                dvOrder.Sort = "Time DESC";                DataTable dtinfo = dvOrder.ToTable();                if (this.dataGridView.InvokeRequired)                {                    SetMessageCallBack stms = new SetMessageCallBack(BindMessage);                    if (this != null)                    {                        this.Invoke(stms, new object[] { dtinfo });                    }                }                else                {                    dataGridView.DataSource = dvOrder.ToTable();                }            }                    }        /// <summary>        /// 列表显示最新消息        /// </summary>        /// <param name="dt"></param>        private void BindMessage(object dt)        {            dataGridView.DataSource = dt;        }        /// <summary>        /// 获取所有表信息        /// </summary>        /// <returns></returns>        public DataTable GetAllTableInfo()        {            string strSQL = @"    SELECT T.name AS table_name ,            T.object_id AS tableid,            ISNULL(CONVERT(VARCHAR(MAX), E.value), '') AS table_name_c ,            C.name AS field_name ,            ISNULL(CONVERT(VARCHAR(MAX), D.value), '') AS field_name_c ,            ROW_NUMBER() OVER(PARTITION BY T.name ORDER BY C.colid) AS field_sequence ,            TYPE_NAME(C.xtype) AS date_type ,            (CASE WHEN EXISTS ( SELECT   1            FROM     sysobjects            WHERE    xtype = 'PK'            AND name IN (            SELECT  name            FROM    sysindexes            WHERE   id = C.id            AND indid IN (            SELECT  indid            FROM    sysindexkeys            WHERE   id = C.id            AND colid = C.colid ) ) )            THEN 1            ELSE 0            END) AS pk ,            ISNULL(C.isnullable, 1) AS isnullable ,            ISNULL(COLUMNPROPERTY(c.id, c.name, 'IsIdentity'), 0) AS isidentity            FROM   sys.tables AS T            LEFT JOIN syscolumns AS C ON c.id = T.object_id            LEFT JOIN sys.extended_properties AS D ON D.major_id = T.object_id            AND D.minor_id = C.colid            AND D.major_id = C.id            LEFT JOIN sys.extended_properties AS E ON E.major_id = T.object_id            AND E.minor_id = 0        WHERE T.object_id IN (SELECT object_id FROM sys.Tables)";            return CPQuery.From(strSQL).FillDataTable();        }    }}

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2.BackgroundWorker

除了自己使用Thread或者ThreadPool来实现跨线程更新UI还可以使用BackgroundWorker组件来实现该效果。

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using Mysoft.Map.Extensions.DAL;using System.Collections;using Mysoft.Code.Services;using System.IO;using System.Threading;namespace ThreadWin{    public partial class BackgroundWorkerForm : Form    {        //模版文件路径        private static string tmpPath = AppDomain.CurrentDomain.BaseDirectory + @"实体模版\Entity.vm";        //模版输出路径        private static string outPutPath = AppDomain.CurrentDomain.BaseDirectory + @"模版输出路径";        private DataTable dtInfo = new DataTable();        /// <summary>        /// 消息发送请求委托        /// </summary>        /// <param name="Msg">消息</param>        delegate void SetMessageCallBack(object Msg);        public BackgroundWorkerForm()        {            InitializeComponent();            dtInfo.Columns.Add("TableName");            dtInfo.Columns.Add("Info");            dtInfo.Columns.Add("Time");            Control.CheckForIllegalCrossThreadCalls = false;        }        private void btn_OK_Click(object sender, EventArgs e)        {            dtInfo.Clear();                        if (!Directory.Exists(outPutPath))            {                Directory.CreateDirectory(outPutPath);            }            //判断线程是否Busy            if (mBackgroundWorker.IsBusy)            {                MessageBox.Show("当前进程正在生成代码，请等待本次操作完成！");                return;            }            mBackgroundWorker.RunWorkerAsync();        }        private void mBackgroundWorker_DoWork(object sender, DoWorkEventArgs e)        {            BackgroundWorker bw = (BackgroundWorker)sender;            //循环生成实体，并且在列表上显示进度            DataTable dt = GetAllTableInfo();            DataView dv = dt.DefaultView;            var query = (from p in dt.AsEnumerable()                         group p by new { TableId = p.Field<int>("tableid"), TableName = p.Field<string>("table_name") } into q                         select new { TableId = q.Key.TableId, TableName = q.Key.TableName }                        );            foreach (var key in query)            {                dv.RowFilter = "tableid=" + key.TableId;                DataTable dtTable = dv.ToTable();                Hashtable ht = new Hashtable();                ht["T"] = dtTable;                string tableName = dtTable.Rows[0]["table_name"].ToString();                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, key.TableName));                //消息提示                DataRow dr = dtInfo.NewRow();                dr["TableName"] = tableName;                dr["Info"] = "生成成功";                dr["Time"] = DateTime.Now.ToString();                dtInfo.Rows.Add(dr);                DataView dvOrder = dtInfo.DefaultView;                dvOrder.Sort = "Time DESC";                DataTable dtinfo = dvOrder.ToTable();                //通知进度改变                bw.ReportProgress(0, dtinfo);            }         }        /// <summary>        /// 进度改变执行        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void mBackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)        {            dataGridView.DataSource = e.UserState;        }        /// <summary>        /// 获取所有表信息        /// </summary>        /// <returns></returns>        public DataTable GetAllTableInfo()        {            string strSQL = @"    SELECT T.name AS table_name ,            T.object_id AS tableid,            ISNULL(CONVERT(VARCHAR(MAX), E.value), '') AS table_name_c ,            C.name AS field_name ,            ISNULL(CONVERT(VARCHAR(MAX), D.value), '') AS field_name_c ,            ROW_NUMBER() OVER(PARTITION BY T.name ORDER BY C.colid) AS field_sequence ,            TYPE_NAME(C.xtype) AS date_type ,            (CASE WHEN EXISTS ( SELECT   1            FROM     sysobjects            WHERE    xtype = 'PK'            AND name IN (            SELECT  name            FROM    sysindexes            WHERE   id = C.id            AND indid IN (            SELECT  indid            FROM    sysindexkeys            WHERE   id = C.id            AND colid = C.colid ) ) )            THEN 1            ELSE 0            END) AS pk ,            ISNULL(C.isnullable, 1) AS isnullable ,            ISNULL(COLUMNPROPERTY(c.id, c.name, 'IsIdentity'), 0) AS isidentity            FROM   sys.tables AS T            LEFT JOIN syscolumns AS C ON c.id = T.object_id            LEFT JOIN sys.extended_properties AS D ON D.major_id = T.object_id            AND D.minor_id = C.colid            AND D.major_id = C.id            LEFT JOIN sys.extended_properties AS E ON E.major_id = T.object_id            AND E.minor_id = 0        WHERE T.object_id IN (SELECT object_id FROM sys.Tables)";            return CPQuery.From(strSQL).FillDataTable();        }    }}

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1.操作步骤很简单，从组件里面拖一个BackgroundWorker组件设置WorkerReportsProgress（是否允许通知进度改变）为true

2.添加DoWork(进行耗时操作) 和 ProgressChanged(进度改变执行) 方法

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本章总结

在写数据字典生成工具之前自己对线程的使用还是很模糊的，翻了很多资料和博客才学习到这些知识。如果您感觉本文不错，对您有所帮助，请您不吝点击下右边的推荐按钮，谢谢！

本章代码示例代码下载地址：http://code.taobao.org/svn/DataDic_QuickCode ，请使用SVN进行下载！

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工具源代码下载

目前总共有经过了七个版本的升级，现在提供最新版本的下载地址

数据字典生成工具V2.0安装程序	最新安装程序
数据字典生成工具源代码	最新源代码

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学习使用

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数据字典生成工具之旅(九)：多线程使用及介绍

线程的应用

winform程序中的多线程

本章总结

工具源代码下载

学习使用