how we use the value of textbox which is inside the repeater

Question

<asp:Repeater ID="repeat1" runat="server" DataSourceID="SqlDataSource1">

<asp:TextBox ID="txtbox1" runat="server" Text='<%#Eval("IDM") %>'></asp:TextBox>

<asp:TextBox ID="txtbox2" runat="server" Text='<%#Eval("Productname") %>'></asp:TextBox> 

</ItemTemplate></asp:Repeater>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings:MyConn %>"

SelectCommand="SELECT * FROM [product] WHERE ([IDM] = @IDM)">

<SelectParameters>

<asp:QueryStringParameter DefaultValue="0" Name="IDM" QueryStringField="IDM"

Type="Int32" />

</SelectParameters></asp:SqlDataSource>

 

 

i want to use the  value of txtbox1 & txtbox2 for save the data in database using the code-behind code

but in code-behind txtbox1 and txtbox2 is not show..

any one help me....