public List<FileInfo> GetFiles() {
  string path = string.Concat(System.AppDomain.CurrentDomain.BaseDirectory,"Files\\"); 
  //获取项目物理路径
  string[] fileType=new string[]{"pdf\\","pps\\","xls\\"};
  string[] directoryFiles = new string[] { };
  List<FileInfo> fileInfoList = new List<FileInfo>();
  for (int f = 0; f < fileType.Count(); f++) {
   path = path + fileType[f];
   directoryFiles=System.IO.Directory.GetFiles(path);
  for(int d=0;d<directoryFiles.Count();d++){
   FileInfo fileInfo = new FileInfo(directoryFiles[d]);
   fileInfoList.Add(fileInfo);
   }
  }
  return fileInfoList;
}