I have reviewed the provided sample project and made thе following changes:
1. Subscribe to the CreateCell
event before calling the DefineGroups
2. The custom ExpandCollapseHeaderCellElement
inherits from GridColumnGroupCellElement
3. In the CreateChildElements
method, add directly the RadButtonElement to the Children collection of the cell.
4. In the CreateCell
event replace the default GridColumnGroupCellElement
with the custom one.
Please refer to the attached modified sample project.
Off topic, I would kindly ask you to submit a support ticket from your Telerik account if you have any further questions. Thus, you will be allowed to attach sample projects. Note that most of the forum threads are reviewed by Telerik representatives and sometimes we address the questions asked by our customers in the forums as well. However, a post in the forum doesn't guarantee you a response from the Telerik support team. Moreover, threads are handled according to license and time of posting, so if it is an urgent problem, we suggest you use a support ticket, which would be handled before a forum thread.
I hope this information helps.
Dess | Tech Support Engineer, Sr.
Get quickly onboarded and successful
with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.