I made a small prototype project using your suggestion, and it worked after I published it to Azure.
The issue that I'm now having is that the solution isn't acceptable to my client.
The solution only works when the grid is in in-line edit mode.
I'm using a custom editor template, as the number of fields involved make inline editing unworkable. The client wanted the new application to look as much like the old, familiar, application as possible. I tried to achieve this using a custom editor template.
Is there another possible solution? Is there any other documentation I can look at? Is there maybe a different way to lay out the UI that I haven't thought of?
Oh, and I should probably mention that the current UI uses a 2-tier, hierarchical grid, which list donations for a selected donor. I want to preserve this layout as the client really likes it (and so do I).
Thanks again for the help.