Gergana,

I have a IEnumerable<DataType> where the DataType has upto 20 properties. The IEnumerable has between 10 to 1000 items. I'm grouping the data by upto 4 properties of the DataType. This is fine when there is 1000+ items, all the groups make sense. However when there are only 10 items, 2 of the groups are not required. So I would like to examine the groupings and if the group only contains one group, then remove, turn off or set a setting that stops XamDataGrid to not allow groups with only one group.

 Sorry just realised that I pasted the wrong code snippet in my original post.

I'm doing it just before I'm doing the summaries with this:

if (attributes.Any(attribute => attribute.GroupBy))
{
    if (!XamDataGrid.Resources.Contains("ColourKey"))
    {
        var datatype = typeof (GroupByRecordPresenter);
        var style = new Style(datatype);
        style.Resources.Add(new ComponentResourceKey(typeof (XamDataGrid), "LabelHighlight"), new SolidColorBrush(Colors.Transparent));
        style.Resources.Add(new ComponentResourceKey(typeof (XamDataGrid), "LabelBackground"), new SolidColorBrush(Colors.Transparent));
       
        foreach (var source in attributes.Where(attribute => attribute.GroupBy).OrderBy(attribute => attribute.Order))
        {
            var brush = new LinearGradientBrush() { Opacity = 0.5, StartPoint = new Point(0.5,0), EndPoint = new Point(0.5,1)};
            brush.GradientStops.Add(new GradientStop(Colors.Snow, 0));
            if (source.ColourBinding)
            {
                var stop = new GradientStop(source.ColourCodeFinish, 0.9);
                var binding = new Binding("ChildRecords[0].DataItem." +
                        attributes.FirstOrDefault(attribute => attribute.ColourBound).PropertyName);
                BindingOperations.SetBinding(stop, GradientStop.ColorProperty, binding);
                brush.GradientStops.Add(stop);
            }
            else
            {
                brush.GradientStops.Add(new GradientStop(source.ColourCodeStart, 0.1));
                brush.GradientStops.Add(new GradientStop(source.ColourCodeFinish, 0.9));
            }
            e.FieldLayout.SortedFields.Add(new FieldSortDescription(source.PropertyName,
                ListSortDirection.Ascending, true));
          
            brush.GradientStops.Add(new GradientStop(Colors.Snow, 1));
            var trigger = new DataTrigger() {Value = source.PropertyName};
            trigger.Binding = new Binding("GroupByField.Name") { BindsDirectlyToSource = true };
            trigger.Setters.Add(new Setter(BackgroundProperty, brush));
            style.Triggers.Add(trigger);

        }
        XamDataGrid.Resources.Add("ColourKey", style);
    }
   
    var statbinding = new Binding()
    {
        Source = XamDataGrid.Resources["ColourKey"],
        BindsDirectlyToSource = true
    };
    BindingOperations.SetBinding(XamDataGrid.FieldSettings, FieldSettings.GroupByRecordPresenterStyleProperty, statbinding);
}

here is a screen shot, it turns out very messy with the grouping not doing anything but add confusion. would be great if the control could deal with this.

Hello ahrensd,

Thank you for the provided information.

I have been looking into your issue. In order to remove the groups that have only one item in them you can set the visibility of the GroupByRecord to Collapsed.

I have created a small sample application for you to show you this functionality. In the sample application I have a simple XamDataGrid bound to a collection. Then if you group by the "Age" field you would be able to see that there are only two groups.

Please note, that when you group by more than one field you would have to loop through  the children of the second group to check the count of the items in them.

Please find the attached sample application and feel free to let me know if you have any further questions on this matter.

Have updated your code, I want to disable grouping on a field if the result will give 1 item in each group as happens with grouping LastItem

pic https://cloudstor.aarnet.edu.au/plus/public.php?service=files&t=b8faa73c0670d18cf55d336916687525

Hello ahrensd,

Thank you for the provided sample application.

I have been looking into it and have modified it for you.

In the modified sample application I am checking if the second group has one item in it. If it has I clear the SortedFields collection. In order to preserve the first grouping( by the 'Name' Field) I assign the grouping manually after the SortedFields collection is cleared.

Please find the attached sample application and feel free to let me know if you have any further questions on this matter.

Thanks for your time Gergana,

Your modified code didn't quite cut it, but did put me on the right track, which I would never of found without your help.

After some further alterations I have something that behaves how I wanted.

Any improvements welcomed, how about putting the functionality directly in the library?

Regards David

Hello ahrensd,

I am just checking if you have any further questions on this matter. Please do not hesitate to let me know if you do.

Have used this code for my application and it doesn't work when you programmiclly add the FieldSortDescription's in the FieldLayoutInitialized.

Close but doesn't call igDataGrid_Grouping  in this case.