Hi,

When a user groups the data I have in a data grid, I'd like to be able to specify a custom IComparer sort of the number of items in a group (which I can do by using the GroupByComparer) as the default sort. However, I'd then like the label in the group by area to act as a TriState sort label (as I have it configured to do in the normal group headers), and when the sort arrow appears I'd like it to go back to the default sorting by value. Ascending/Descending and then back to default custom sort.

E.g. If I have a Country column in the grid and I drag it into the group by area, it should initially sort by the number of items in each group (descending), and then when the user clicks it again, it should sort alphabetically ascending, then descending, then back to items in each group (with no sort arrow).

I used the description in https://www.infragistics.com/community/forums/f/ultimate-ui-for-wpf/89424/xamdatagrid-groupbyarea-sort-by-number-of-items-in-a-group-instead-of-the-records-in-the-field to get the custom sort by number of items working (although I had to invert the result because it sorts by ascending first), but I'm then stuck sorting by this method.

Any suggestions on how to achieve this?

Thanks,

Richard