这个功能比较常用，在Data Loader也有一个PDF Watcher的程序，以监控指定的目录是否有新加入的PDF文件（可能来自远程传输，或是从网页中下载回来），然后对它进转换，导入到文档服务器中。

public void StartMonitor(string path)  {                   FileSystemWatcher watcher = new FileSystemWatcher();          watcher.Path = path;             watcher.NotifyFilter = NotifyFilters.FileName;          // Only watch pdf files.          watcher.Filter = "*.pdf";          watcher.Created += new FileSystemEventHandler(OnChanged);          watcher.EnableRaisingEvents = true;  }     // Event handler for when a  file is created in the watched folder  private void OnChanged(object source, FileSystemEventArgs e)  {          string word = DocumentUtility.ConvertPdfToDoc(e.FullPath);  }