ASP.NET assign button onclick at runtime - asp.net

Question

I am using ajax modal popup dialog to make users confirm their action. Since I have several scenarios where the user needs to confirm the action, I would like to re-use the same popup dialog, only changing which event is fired when the user click btnYes (confirming the action).
In code behind (VB) I assign the message for the popup:
lblMessageConfirm.Text = strMessage
Then, before opening the dialog, I would like to assign the event that btnYes will fire if the user clicks. I tried the methods below and none seems to work:
AddHandler btnYes.Click, AddressOf Test '(this event does not do anything)
And also
btnYes.Attributes.Add("onclick", "Test") '(this returns an error “Test is undefined”)
Test1 is the sub I want to assign to “Onclick” and it is in the code behind in the page where the popup is set up:
Protected Sub Test(sender As Object, e As EventArgs)
MsgBox("Test ")
End Sub
I open the dialog:
ModalPopupExtender2.Show()
Here is the html for the popup – it does show up, so the only problem is trying to assign onclick event. When I add the “onclick” in the HTML, the Test sub runs
<cc1:ConfirmButtonExtender ID="cbe" runat="server"
DisplayModalPopupID="ModalPopupExtender2" TargetControlID="lnkDummy">
</cc1:ConfirmButtonExtender>
<cc1:ModalPopupExtender ID="ModalPopupExtender2" runat="server"
PopupControlID="pnlPopup2"
TargetControlID="lnkDummy"
CancelControlID="btnNo" >
</cc1:ModalPopupExtender>
<asp:Panel ID="pnlPopup2" runat="server" CssClass="modalPopup"
Style="display: none">
<div class="ModalHeader" runat="server">
Please Confirm ...
</div>
<div class="ModalBody" runat="server">
<asp:Label ID="lblMessageConfirm" runat="server">
</asp:Label>
</div>
<div class="ModalFooter">
<asp:Button ID="btnYes " runat="server"
CSSClass="ModalButton" Text="OK" />
</div>
</asp:Panel>
With the following code Test runs:
<asp:Button ID="btnYes " runat="server" CSSClass="ModalButton" Text="OK"
onclick="Test"/>
I have this working with 2 Yes buttons and making the correct one visible based on the scenario, but adding more scenarios where the user needs to confirm will mean adding more buttons...