Once you opt to have grouping, all your items will belong to some group – you can’t have “ungrouped” items. You can accomplish what you describe by providing different styles for the groups depending on the number of items within the group. Within the template for the group header, you can have a binding with Path=Items.Count to get the number of items within that group. Then you can use a trigger to control the look of the template (e.g. you may control the visibility of sections of your template).

Bea

It seems to me that you’re looking for custom sorting. I have a blog post that explains how you can do that.

Yes, it’s possible to recalculate/refresh the view. If you’re using CollectionViewSource, you can do that using cvs.View.Refresh().

Bea

Sorry I didn’t have a chance to get to your question earlier. I’m glad you found a solution.

Bea

This is somewhat related to your post above…I have 2 problems and I’m not sure what is causing them. I have explained them here http://forums.silverlight.net/forums/t/140407.aspx
From reading your blog I imagine you would well able to explain what is happening.

I hope you have the time to look!

DavidO

Regarding the collection groupings, is it possible to have items that do not belong to a group ? In my case I use an expander for the categoryTemplate allowing me to expand/collapse the groups. I would like that groups with a single element in them don’t have an expander associated (so they won’t show the group element). Is this even possible?

Alex.

I replied to that question in the comment you left on another post: http://bea.stollnitz.com/blog/?p=24&cpage=1#comment-166488.

Bea

I was wondering if there is a way to insert a converter in the SortDescription? I have a GroupDescription created from an IEnumerable (with a converter) and I would like the grouping to be sorted (ie. Group A always before Group Z). Is there a way to extend the SortDescription class to allow a Converter?

I’d also like to know if its possible to delay grouping calculation or force a recalculation? I am using a CollectionViewSource on my ViewModel collection, but the grouped property is lazy loaded internally. I have found that when the real value is finally loaded the grouping is not updated. Can I force a recalculation?

Thanks for the help,

Vanja