Insert Another Gridview2 Which Is Child Gridview Inside Every Row Of Parent Gridview - C#

I have a gridview1 which is the parent gridview and I want to insert another gridview2 which is child gridview inside every row of parent gridview This is the code in the .aspx

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<asp:GridView ID="GridView1" runat="server">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:GridView ID="gridView2" runat="server">
</asp:GridView>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

This is the code that I have added inside the RowDataBound Event and i'm just binding the gridview2 with the arraylist which is filtered data depending upon the contents of each row's invoice number.................