Data Controls :: Loop Through Parent And Child / GridView And Same Data To Database

 I have nested gridviews, in the outer grid I am displaying the question and in the inner grid 4 options are displayed in radiobuttons.  I have kept Lock Answer button inside Item Template in inner gridview , so this button is coming with each and every question and when i click on Lock Answer button in front of any question, its saving the corresponding answer in the database. For ex, if there are 10 questions this button is coming with all the questions, all the questions are on single page and all are multiple choice. Now everything is working mine, my requirement is that I need on 1 common Lock Answer button at the bottom of the page and not with all the questions. And when I click on that common button it should run for all the questions that are displayed on the screen at should fetch and update each unique answer corresponding to that question in the database. Below is my code:

<asp:GridView ID="gvouter" runat="server" GridLines="None" AutoGenerateColumns="False"
AllowPaging="false" OnRowDataBound="gvouter_RowDataBound" Width="100%" OnRowCommand="gvouter_RowCommand"
OnPageIndexChanging="gvouter_PageIndexChanging" >
<PagerSettings Position="Top" />
<Columns>
<asp:TemplateField>
<ItemTemplate>

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