Image button in each row that should pass row data as parameters to the new webform opened in a popup

I have an image button in each gridview row that should pass some row data as parameters to the new webform being opened in a popup. I am not sure what do I need to do to get the event fired. Currently when I click on the image button nothing happens. Here is the markup for the image button:
<ItemTemplate> <asp:ImageButton ID="ImagebtnAddress" runat="server" CommandName="GetAddress" ImageUrl="~/Images/Address.jpg" Height="16px" Width="16px" tooltip="Address Details"/> </ItemTemplate>
Here is the gridview event code that's not firing in the code behind when the image button is clicked. I tried "if e.CommandName = GetAddress" also but it didn't work, it's like the event is not bound to the click of the image button. Do I need to create a click event or the RowDataBound event should work?
Protected Sub gvAddress_RowDataBound(ByVal sende ...