colouring rows based on id of model

Question

i want unique color to the table rows to identify all records of that InternalTaskID (which can be taken from Model) currently I'm doing this...

    @{
       var rowColor = "#dfd6fa";
     }

     @foreach (var item in Model)
     {
          if(item.InternalTaskID.Equals(Unique_TaskIDs.First()))
          {
            rowColor = "#dfd6fa";
          }
          else
          {
            rowColor = "#ffffff";
          }
          <tr style="background-color:@rowColor;">
          ...
          ...
         </tr>
     }

but this will work only for rows with the same first id, currently i need to know

1. How to get unlimited supply of unique colours and use them without repetition
2. assigning these colors to the Unique_ids
3. combine Unique_ids and unique_colors to get the required View

how do i do it?