Keep GridViewRows highlighted when paging

Dictionary<int,> dictionary = new Dictionary<int,>();

if(!Session["ListValue"])
{
       dictionary =(Dictionary<int,bool>)Session["ListValue"]
}

index = Convert.ToInt32(e.CommandArgument)
          If selectedRow.BackColor = Color.Orange Then
            selectedRow.BackColor = System.Drawing.ColorTranslator.FromHtml("#738A9C")
            strPanr = selectedRow.Cells(1).Text
         if(dictionary.ContainsKey(index))
          { 
        dictionary[index]=false;
          } 
else
{
dictionary.Add(index,false)
}
          Else
            selectedRow.BackColor = Color.Orange
            strPanr = selectedRow.Cells(1).Text
 if(dictionary.ContainsKey(index))
          { 
          dictionary[index]=true;
          } 
else
{
       dictionary.Add(index,true)
}

          End If
Session["ListValue"]=dictionary;