Forms Data Controls :: Create A Second Grid In The Same Page With Detailed Info For A Given Record Of The First Grid

I am trying to create a second grid in the same page with detailed info for a given record of the first Grid, but when I press select in the first grid nothing happens. I follwed everything I read.

<asp:GridView runat="server" AutoGenerateColumns="False"
DataSourceID="SqlDataSource1" style="margin-right: 0px" Width="659px"
AutoGenerateDeleteButton="True" AutoGenerateEditButton="True"
AllowSorting="True" DataKeyNames="accession_num,organ"
EnablePersistedSelection="True" EnableSortingAndPagingCallbacks="True" onselectedindexchanged="Unnamed1_SelectedIndexChanged"
>
<Columns>
<asp:BoundField DataField="organ" HeaderText="organ"
SortExpression="organ" />
<asp:BoundField DataField="weight" HeaderText="weight"
SortExpression="weight" />
<asp:BoundField DataField="unit" HeaderText="unit" SortExpression="unit" />
<asp:BoundField DataField="accession_num" HeaderText="accession_num"
ReadOnly="True" />
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%&#36; ConnectionStrings:pdmstestConnectionString %>"
SelectCommand="GetGrossOrgan" SelectCommandType="StoredProcedure"
UpdateCommand="UpdateGrossOrgan" UpdateCommandType="StoredProcedure"
DeleteCommand="DELETE FROM [Pathology_Gross_Organ] WHERE [accession_num] = @accession_num AND [organ] = @original_organ"
OldValuesParameterFormatString="original_{0}"
> <SelectParameters>
<asp:ControlParameter ControlID="accession_num" Name="accession_num"
PropertyName="Text" Type="String"/>
</SelectParameters>
<DeleteParameters>
<asp:Parameter Name="accession_num" Type="String" />
<asp:Parameter Name="original_organ" Type="String"/>
</DeleteParameters>
<UpdateParameters>
<asp:Parameter Name="accession_num" Type="String"/>
<asp:Parameter Name="organ" Type="String"/>
<asp:Parameter Name="weight" Type="Int16" />
<asp:Parameter Name="unit" Type="String"/>
</UpdateParameters>
</asp:SqlDataSource>