FileSystemWatcher watcherName = new FileSystemWatcher();
            watcherName.IncludeSubdirectories = false;
            watcherName.Filter = "*.txt";
            watcherName.Path = ulrValue + @"\";
            watcherName.Created += new FileSystemEventHandler(watcherName_Created);//新增事件
　　　　　　　//watcherName存在 删除 修该 更改文件名的事件

　　　　　　　watcherName.EnableRaisingEvents = true;