数据字典生成工具之旅(9)：多线程使用及介绍

阅读量：7251 次

发布时间：2019-06-29

本文共 14821 字，大约阅读时间需要 49 分钟。

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

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

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{    ///     /// 代码生成类    /// 
    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;        ///         /// 批量生成代码        /// 
        /// 模版文件参数        public static void BatchGenerator(List
       
         args)        {            if (!Directory.Exists(outPutPath))            {                Directory.CreateDirectory(outPutPath);            }            //生成文件数量
        
          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
         
          
           > threadParams = new List
           
            
             >(); for (int i = 0; i < threadCount; i++) { threadParams.Add(args.Skip(total).Take(threadPqgeSize).ToList()); total += threadParams[i].Count; } //创建线程 List
             
               threads = new List
              
               (); 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
               
                 list = (List
                
                 )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。

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();        ///         /// 消息发送请求委托        /// 
        /// 消息        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);        }        ///         /// 这里进行耗时的生成代码操作        /// 
        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
      
       ("tableid"), TableName = p.Field
       
        ("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();                }            }                    }        /// 
                /// 列表显示最新消息        /// 
        /// 
                private void BindMessage(object dt)        {            dataGridView.DataSource = dt;        }        /// 
                /// 获取所有表信息        /// 
        /// 
                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();        ///         /// 消息发送请求委托        /// 
        /// 消息        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
      
       ("tableid"), TableName = p.Field
       
        ("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);            }         }        /// 
                /// 进度改变执行        /// 
        /// 
                /// 
                private void mBackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)        {            dataGridView.DataSource = e.UserState;        }        /// 
                /// 获取所有表信息        /// 
        /// 
                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

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

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：，请使用SVN进行下载！

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

	最新安装程序
	最新源代码
	SVN最新源码共享地址

学习使用

如果你使用了该工具，或者想学习该工具，欢迎加入这个小组，一起讨论数据字典生成工具、把该工具做的更强，更方便使用，一起加入。

更多数据字典生成工具资料请点击。

如果，您认为阅读这篇博客让您有些收获，不妨点击一下右下角的按钮。

如果，您希望更容易地发现我的新博客，不妨点击一下绿色通道的【关注我】。

如果，想给予我更多的鼓励，

求打

因为，我的写作热情也离不开您的肯定支持。

感谢您的阅读，如果您对我的博客所讲述的内容有兴趣，请继续关注我的后续博客，我是焰尾迭。

转载地址：http://ophbm.baihongyu.com/

你可能感兴趣的文章