Removing null Datapoint in ASP.NET Chart Series

<asp:Chart ID="Chart2" runat="server"  Width="800px">
           <Legends>
               <asp:Legend Docking="Left" BackColor="#cccccc"></asp:Legend>
           </Legends>
           <Series>
               <asp:Series Name="Series1" ChartType="Column" XValueType="String" ChartArea="ChartArea2" >
                   <Points>
                       <asp:DataPoint XValue="1" YValues="20"  />
                       <asp:DataPoint XValue="2" YValues="10" />
                       <asp:DataPoint XValue="3" YValues="30" />
                   </Points>
               </asp:Series>
               <asp:Series Name="Series2" ChartType="Column" XValueType="String" ChartArea="ChartArea2">
                   <Points>
                       <asp:DataPoint XValue="1" YValues="20" />
                       <!-- here is missed datapoint -->
                       <asp:DataPoint XValue="3" YValues="30" />
                   </Points>
               </asp:Series>
                <asp:Series Name="Series3" ChartType="Column"  XValueType="String" ChartArea="ChartArea2">
                   <Points>
                       <asp:DataPoint XValue="1" YValues="100" />
                       <asp:DataPoint XValue="2" YValues="100" />
                       <asp:DataPoint XValue="3" YValues="100" />
                   </Points>
               </asp:Series>
           </Series>
           <ChartAreas>
               <asp:ChartArea Name="ChartArea2">
               </asp:ChartArea>
           </ChartAreas>
       </asp:Chart>