How to integrate timereport after checkin in TFS?

We would like to integrate an extra popup开发者_运维问答/prompt when a user checks in something and associating it with a work item. The prompt should ask the user how much time he spent and how much time is left on the work item. This will work as timesheet material for the timereport and invoice. Has anybody any experience to share in this matter? Is this a Check-in policy? A web service trigger? Is it possible?

A custom check-in policy is your best bet. Certainly possible to do that way.

The downside is that it won't catch people just updating a work item without checking things in.