1 <div style="OVERFLOW-Y:scroll;   HEIGHT:1000px">
2           <asp:CheckBoxList ID="RBL_List" runat="server" RepeatColumns="<%#GetColumns()%>" RepeatDirection="Horizontal"    Width="90%"  ></asp:CheckBoxList>
3         </div>

 1  public int GetColumns()
 2     {
 3         int count = dtItem.Rows.Count;
 4         if (count <= 20)
 5         {
 6             return 2;
 7         }
 8         else if (count > 20 && count <= 60)
 9         {
10             return 3;
11         }
12         else
13         {
14             return 4;
15         }
16     }