I have encountered a problem while using the GroupFooterTemplate in RadGrid. I have implemented a RadGrid using GroupFooterTemplate according the documentation that I have found at your web site. Here is the link to the documentation:
Group Header and Footer Templates
In the GroupFooterTemplate, I used several <td></td> together with labels to show the footer items. I have to use GroupFooterTemplate because a checkbox must be displayed in one of the footer columns.
The issue occured, when I used Aggregate="Custom" as follows
<telerik:GridBoundColumn UniqueName="OrderNo" DataField="OrderNo" HeaderText="Order No." Aggregate="Custom" />
The error message that I got is as follows:
An entry with the same key already exists.
Exception Details: System.ArgumentException: An entry with the same key already exists.
If I used Aggregate="Sum" or Aggregate="Count" instead of Aggregate="Custom" , the web application could run without error. Could you please tell me how to use aggregate custom correctly while using the GroupFooterTemplate?
Many thanks in advance!