1:  public static class Data

   2:  {

   3:     private static string _userId;

   4:     public static string UserId

   5:     {

   6:        get { return _userId; }

   7:        set { _userId = value; }

   8:     }

   9:   

  10:     public static void SetUser(string userId)

  11:     {

  12:        UserId = userId;

  13:     }

  14:  }