title: List Occurence wise read c#
body: <p>I have Class Like this</p>
  
  <pre><code>  public  class RoomDetails
    {
       public int RoomIndexID {get;set;} --(This is No of Rooms)
       public int roomcategoryID {get;set;} -- (This is No of Category that room have)
       public decimal roomPrice{get;set;}
       public string roomCategory{get;set;}
    }
  </code></pre>
  
  <p>So i have RoomDetails List like this(data)</p>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,1,250,Double Bed</li>
  <li>2,2,400,Double Bed with Extra View</li>
  <li>2,4,530,Tripple Bed</li>
  <li>3,1,530,Tripple Bed</li>
  <li>3,2,600,Triple Large Bed</li>
  </ul>
  
  <p>so i want to read this list following procedure.</p>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,1,250,Double Bed</li>
  <li>3,1,530,Tripple Bed</li>
  </ul>
  
  <hr>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,1,250,Double Bed</li>
  <li>3,2,600,Triple Large Bed</li>
  </ul>
  
  <hr>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,2,400,Double Bed with Extra View</li>
  <li>3,1,530,Tripple Bed</li>
  </ul>
  
  <hr>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,2,400,Double Bed with Extra View</li>
  <li>3,2,600,Triple Large Bed</li>
  </ul>
  
  <hr>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,4,530,Tripple Bed</li>
  <li>3,1,530,Tripple Bed</li>
  </ul>
  
  <hr>
  
  <ul>
  <li>1,1,200,Single Bed</li>
  <li>2,4,530,Tripple Bed</li>
  <li>3,2,600,Triple Large Bed</li>
  </ul>
  
  <p>please ask if you have any problem regrading my question.</p>
  
  <p>This is example</p>
  
  <p>my data list is like this</p>
  
  <ul>
  <li>Room A  -- A1</li>
  <li>Room B  -- B1 , B2 , B3</li>
  <li>Room C  -- C1 , C2</li>
  </ul>
  
  <p>(Actually A ,B, C means RoomIndexID 's and A1,B1,B2,B3,C1,C2 is roomcategoryID 's)
  so I want to read it like this.</p>
  
  <ul>
  <li>A1,B1,C1</li>
  <li>A1,B1,C2</li>
  <li>A1,B2,C1</li>
  <li>A1,B2,C2</li>
  <li>A1,B3,C1</li>
  <li>A1,B3,C2</li>
  </ul>