display a popup on a Repeater control with textbox and confirmation button - asp.net

Question

So i have a .NET page in which i have a repeater and a "delete" button for every record in this repeater.
what i want to do is to display a popup each time this button is clicked,where the user could enter a text and confirm the deletion.
i already have my deleting method working and i'm having trouble with the displying popup part.
i've tried AjaxToolkit : popupExtender but can' t configure it correctly , it doesn't popup doesn't recognise button id .
<ajaxToolkit:ToolkitScriptManager
ID="ToolkitScriptManager1" runat="server">
</ajaxToolkit:ToolkitScriptManager>
<div
<p style="width: 125px; margin-left: 520px">
</p>
<asp:Repeater ID="Repeater1" runat="server" EnableTheming="true" onitemcommand="Repeater1_ItemCommand" >
<HeaderTemplate>
<table class="datatable fullwidthpercent">
<tr>
<td>ID&nbsp</td>
<td>&nbsp Nom&nbsp</td>
<td>&nbsp Prénom&nbsp</td>
<td>&nbsp Email&nbsp</td>
<td>&nbsp Adresse&nbsp</td>
<td>&nbsp Ville&nbsp</td>
<td>&nbsp Tél&nbsp</td>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>&nbsp<%# Eval("id") %>&nbsp</td>
<td>&nbsp<%# Eval("nom") %>&nbsp</td>
<td>&nbsp<%# Eval("prenom") %>&nbsp</td>
<td>&nbsp<%# Eval("email") %>&nbsp</td>
<td>&nbsp<%# Eval("adresse") %>&nbsp</td>
<td>&nbsp<%# Eval("ville") %>&nbsp</td>
<td>&nbsp<%# Eval("tel") %>&nbsp</td>
<td><asp:Button ID="Btn1" runat="server" CommandArgument= ' <%# Eval("id") %> ' Text="Eliminer" OnClick = "buttonEliminer_click" ></asp:Button></td>
</tr>
</ItemTemplate>
<SeparatorTemplate>
<tr>
<td colspan="6"><hr /></td>
</tr>
</SeparatorTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
</div>
</form>
<ajaxToolkit:PopupControlExtender runat="server" TargetControlID="Btn1"></ajaxToolkit:PopupControlExtender>
and i get the following error :
system.argumentexception argument 'expression' is not a valid value Event validation is enabled using <pages enableEventValidation="true"/>
PS: repeater and database access is working fine.

Answer 1

Try creating a fake button below the ModalPopupExtender such as:
<asp:button runat="server" id="btnFake" style="visibility: collapse;" />
Then set the TargetControlID="btnFake" in the ModalPopupExtender.
In the code behind you can set when a person clicks the delete button, i.e. the buttonEliminer_click routine to:
ModalPopupExtenderID.Show()
Then with buttons on the modal popup to delete from the repeater. This would also mean that you have to gather the ID from the row of the repeater and set it to a HiddenField, for example, in the panel that will be popped up. Then when a person clicks "Submit" on your popup the HiddenField will have the ID of the row to delete.
EDIT: a few notes on your code as well, the popup extender you have added is outside of a </form> section, the popup should be inside this.