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数据字典生成工具之旅(9)：多线程使用及介绍

2015/3/29 20:40:35 焰尾迭程序员俱乐部我要评论(0)

摘要：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回到顶部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
标签：使用多线程工具数据线程

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

回到顶部

class="title">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。

logs_code_hide('f579ef03-6623-4381-a36a-25756dad4236',event)" src="/Upload/Images/2015032920/2B1B950FA3DF188F.gif" alt="" />

--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 BIT
DECLARE @total AS INT 
DECLARE @i AS INT
SELECT @i=1,@total=300,@IsDropTable=0
WHILE @i<=@total
BEGIN
DECLARE @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+1
END

View Code

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()));
            }
        }

    }
}

View Code

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。

回到顶部

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);
            }

View Code

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();
        }
    }
}

View Code

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();
        }
    }
}