一个遍历目录下包含某些内容的所有文件的类

class contentSearch
  {
      private DirectoryInfo _baseDirectory = null;

      public DirectoryInfo BaseDirectory
      {
          get { return _baseDirectory; }
          set { _baseDirectory = value; }
      }
      public contentSearch(string baseDirectory)
      {
          this._baseDirectory = new DirectoryInfo(baseDirectory);
      }

      /// <summary>
      /// 递归匹配包含指定内容的文件全名
      /// </summary>
      /// <param name="dir"></param>
      /// <param name="content"></param>
      /// <param name="reval"></param>
      public void GetFiles(DirectoryInfo dir, string content, ref List<string> reval)
      {

          if (dir.Exists)
          {

              foreach (FileInfo f in dir.GetFiles())
              {
                  if (IsIncludeFile(f))
                  {
                      using (StreamReader sr = File.OpenText(f.FullName))
                      {
                          String input;
                          while ((input = sr.ReadLine()) != null)
                          {
                             // Console.WriteLine(input);
                              if (this.IsExistsContent(input.ToLower(), content))
                              {
                                  reval.Add(f.FullName);
                                  break;
                              }
                          }
                          Console.WriteLine("The end of the stream has been reached.");
                          sr.Close();
                      }
                  }
              }

              foreach (DirectoryInfo subDir in dir.GetDirectories())
              {
                  this.GetFiles(subDir, content, ref reval);

              }

          }

      }

      /// <summary>
      /// 是否是不包括的扩展名
      /// </summary>
      /// <param name="f"></param>
      /// <returns></returns>
      private bool IsExcludeFile(FileInfo f)
      {
          bool reval = false;
          string[] excludeFileType = new string[] { ".exe", ".bak" };
          foreach (string s in excludeFileType)
          {
              if (f.Extension.ToLower() == s)
              {
                  reval = true;
                  break;
              }
          }
          return reval;
      }

      /// <summary>
      /// 是否是包括的扩展名
      /// </summary>
      /// <param name="f"></param>
      /// <returns></returns>
      private bool IsIncludeFile(FileInfo f)
      {
          bool reval = false;
          string[] excludeFileType = new string[] { ".asp", ".aspx", ".cs" };
          foreach (string s in excludeFileType)
          {
              if (f.Extension.ToLower() == s)
              {
                  reval = true;
                  break;
              }
          }
          return reval;
      }

      /// <summary>
      /// 读取的信息是否存在给定的内容中的一个，存在返回true
      /// </summary>
      /// <param name="sourceString"></param>
      /// <param name="content"></param>
      /// <returns></returns>
      private bool IsExistsContent(string sourceString, string content)
      {
          bool reval = false;
          foreach (string s in content.Split(','))
          {
              if (sourceString.Contains(s))
              {
                  reval = true;
                  break;
              }
          }
          return reval;
      }

      /// <summary>
      /// 根据源list中的文件和查询关键字列表，输出文件包含的关键字
      /// </summary>
      /// <param name="filelist"></param>
      /// <param name="keywords"></param>
      /// <returns><code>List<文件名：关键字1，关键字2...></code></returns>
      public List<string> GetContentsOperation(List<string> filelist, string keywords)
      {
          List<string> reval = new List<string>();
          foreach (string file in filelist)
          {

              string original = file + ":  ";
              string revalFile = original;

              StreamReader sr = File.OpenText(file);
              string input;
              while ((input = sr.ReadLine()) != null)
              {
                  string revalkewords=Getkeywords(input.ToLower(), keywords);
                  if (!string.IsNullOrEmpty(revalkewords))
                  {
                      revalFile = revalFile == original ? revalFile + revalkewords : revalFile + "," + revalkewords;
                  }
              }
              reval.Add(revalFile);
          }
          return reval;
      }

      /// <summary>
      /// 读取源字符串中包含关键字，包含多项以逗号分隔
      /// </summary>
      /// <param name="sourceString"></param>
      /// <param name="keywords"></param>
      /// <returns>关键字1，关键字2...</returns>
      private string Getkeywords(string sourceString, string keywords)
      {
          string reval = string.Empty;
          foreach (string s in keywords.Split(','))
          {

              if (sourceString.Contains(s))
              {
                  reval = reval == string.Empty ? s : reval + "," + s;
              }
          }
          return reval;
      }
  }