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C#采用FileSystemWatcher实现监视磁盘文件变更的方法

c#文件方法 实现 磁盘 采用 变更 监视
2023-06-13 09:15:30 时间

本文实例讲述了C#采用FileSystemWatcher实现监视磁盘文件变更的方法。分享给大家供大家参考。具体实现方法如下：

简化需求：有一个简化了的需求是这样的：有一个拍照程序在运行，一旦抓拍之后则将图片文件存储至某目录，然后图片要上传至远程服务器并update数据库。

原需求：原先的需求是这样的：有一台PDA扫码枪，一个IP照相机放置在下线区传送带上方。当PDA扫描箱子上的条码，触发相机拍照，将图片流传至远端服务器，找到对应的条码，将图片存储并更新数据库。

然而我不知道PDA扫描的瞬间如何与IP相机通信（蓝牙或WLAN？），其实关键是我不知道怎样使用IP相机的外触发功能，增加蓝牙触发器？也不知道怎样hack或ssh到这个相机（应该是linux的吧），所以只能先使用简化需求的版本。

而简化需求的版本，关键就是监视文件夹内容变化与上传文件流。

昨天问了下度娘，C#中的监视组件名字叫做FileSystemWatcher。

于是写了个demo，可以监视所有逻辑盘或者某个文件夹。

使用方法：

1.直接打开是监视所有逻辑磁盘文件变化。

2.或者传递参数，监视某一路径文件变化。如图，监视e盘

源代码如下：

复制代码代码如下:


namespaceFileSystemWatcherDemo
{
   classProgram
   {
       staticvoidMain(string[]args)
       {
           //watcher组
           FileSystemWatcher[]watchers;

           //若未传递参数,则监视所有文件系统,包括CD-ROM（不可用）,可移动磁盘（不可用）等
           if(args.Length==0)
           {
               string[]drivers=Directory.GetLogicalDrives();
               watchers=newFileSystemWatcher[drivers.Length];

               for(inti=0;i<drivers.Length;i++)
               {
                   try
                   {
                       watchers[i]=newFileSystemWatcher{Path=drivers[i]};
                   }
                   catch(Exceptionex)
                   {
                       Trace.TraceWarning(ex.Message);
                   }
               }
           }
           else
           {
               watchers=newFileSystemWatcher[1];
               watchers[0]=newFileSystemWatcher{Path=args[0]};
           }

           foreach(FileSystemWatcherwinwatchers)
           {
               if(w==null)continue;

               w.Filter="*";
               w.IncludeSubdirectories=true;
               w.EnableRaisingEvents=true;

               w.Created+=onFileSystem_Changed;
               w.Deleted+=onFileSystem_Changed;
               w.Changed+=onFileSystem_Changed;
               w.Renamed+=watcher_Renamed;
           }

           Console.ReadLine();
       }

       #region[检测文件是否占用]
       ///<summary>
       ///检测文件是否占用
       ///</summary>
       ///<paramname="filename"></param>
       ///<returns></returns>
       staticboolIsFileReady(stringfilename)
       {
           varfi=newFileInfo(filename);
           FileStreamfs=null;
           try
           {
               fs=fi.Open(FileMode.Open,FileAccess.Read,FileShare.None);
               returntrue;
           }
           catch(IOException)
           {
               returnfalse;
           }

           finally
           {
               if(fs!=null)
                   fs.Close();
           }
       }
       #endregion

       privatestaticvolatileobject_lock=true;
       staticvoidonFileSystem_Changed(objectsender,FileSystemEventArgse)
       {
           lock(_lock)
           {
               Console.ForegroundColor=ConsoleColor.DarkGray;
               Console.Write("[");
               Console.Write(DateTime.Now.ToString("HH:mm:ss"));
               Console.Write("]");

               switch(e.ChangeType.ToString().ToLower())
               {
                   case"created":
                       //while(!IsFileReady(e.FullPath))
                       //{
                       //   if(!File.Exists(e.FullPath))
                       //       return;
                       //   Thread.Sleep(100);
                       //}
                       Console.ForegroundColor=ConsoleColor.Green;
                       Console.Write(e.ChangeType);
                       Console.ForegroundColor=ConsoleColor.White;
                       Console.Write("");
                       Console.Write(e.Name);
                       Console.Write("");
                       Console.ForegroundColor=ConsoleColor.DarkGray;
                       Console.Write(e.FullPath);

                       break;
                   case"deleted":
                       Console.ForegroundColor=ConsoleColor.Red;
                       Console.Write(e.ChangeType);
                       Console.ForegroundColor=ConsoleColor.White;
                       Console.Write("");
                       Console.Write(e.Name);
                       Console.Write("");
                       Console.ForegroundColor=ConsoleColor.DarkGray;
                       Console.Write(e.FullPath);
                       break;
                   case"changed":
                       Console.ForegroundColor=ConsoleColor.Cyan;
                       Console.Write(e.ChangeType);
                       Console.ForegroundColor=ConsoleColor.White;
                       Console.Write("");
                       Console.Write(e.Name);
                       Console.Write("");
                       Console.ForegroundColor=ConsoleColor.DarkGray;
                       Console.Write(e.FullPath);
                       break;
               }

               Console.Write("\r\n");
           }
       }
       staticvoidwatcher_Renamed(objectsender,RenamedEventArgse)
       {
           Console.ForegroundColor=ConsoleColor.Magenta;
           Console.Write(e.ChangeType);
           Console.ForegroundColor=ConsoleColor.White;
           Console.Write("");
           Console.Write(e.OldName);
           Console.Write(e.OldFullPath);
           Console.ForegroundColor=ConsoleColor.Yellow;
           Console.Write("");
           Console.Write(e.Name);
           Console.Write(e.FullPath);
           Console.Write(Thread.CurrentThread.Name);
           Console.Write("\r\n");
       }
   }
}

希望本文所述对大家的C#程序设计有所帮助。

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