Scrolling problem with GroupDescriptions

[Geoffrey]

Hello,

I have a problem with the RadComboBox control. The telerik version that I use is Q1 2014.

When I group data using ICollectionViewSource, the data are well grouped but some items are not accessible because the scroll go directly to the next group.

How can I solve that problem ?

The code of the Group style is defined below:

01.public FormatBox()
02.        {
03.            this.IsEditable = false;
04.            this.EmptyText = Translator.Translate("Generic_SelectFormat");
05.
06.
07.            ScrollViewer.SetCanContentScroll(this, true);
08.
09.            DataTemplate itemTemplate = new DataTemplate();
10.
11.            FrameworkElementFactory stackPanelFactory = new FrameworkElementFactory(typeof(StackPanel));
12.            stackPanelFactory.SetValue(StackPanel.OrientationProperty, System.Windows.Controls.Orientation.Horizontal);
13.
14.            FrameworkElementFactory textBlock = new FrameworkElementFactory(typeof(TextBlock));
15.            textBlock.SetBinding(TextBlock.TextProperty, new Binding("Name"));
16.            stackPanelFactory.AppendChild(textBlock);
17.
18.            textBlock = new FrameworkElementFactory(typeof(TextBlock));
19.            textBlock.SetValue(TextBlock.TextProperty, " - ");
20.            stackPanelFactory.AppendChild(textBlock);
21.
22.            textBlock = new FrameworkElementFactory(typeof(TextBlock));
23.            textBlock.SetBinding(TextBlock.TextProperty, new Binding("Description"));
24.            stackPanelFactory.AppendChild(textBlock);
25.
26.            itemTemplate.VisualTree = stackPanelFactory;
27.
28.            this.ItemTemplate = itemTemplate;
29.
30.
31.            GroupStyle style = new GroupStyle();
32.            style.HidesIfEmpty = true;
33.
34.            DataTemplate headerTemplate = new DataTemplate();
35.
36.            textBlock = new FrameworkElementFactory(typeof(TextBlock));
37.            textBlock.SetBinding(TextBlock.TextProperty, new Binding("Name") { Converter = new FormatBoxBooleanToTranslationConverter() });
38.            textBlock.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold);
39.            textBlock.SetValue(FrameworkElement.MarginProperty, new Thickness(5, 0, 5, 0));
40.            textBlock.SetValue(FrameworkElement.VerticalAlignmentProperty, VerticalAlignment.Center);
41.            style.HeaderTemplate = headerTemplate;
42.
43.            FrameworkElementFactory border = new FrameworkElementFactory(typeof(Border));
44.            border.SetValue(Border.BackgroundProperty, new SolidColorBrush(System.Windows.Media.Color.FromArgb(255, 227, 239, 255)));
45.            border.SetValue(FrameworkElement.HeightProperty, 20d);
46.
47.            border.AppendChild(textBlock);
48.
49.            headerTemplate.VisualTree = border;
50.
51.            this.GroupStyle.Add(style);
52.        }

Thanks in advance, this problem is critical for us.
Geofrrey

[Rosen Vladimirov]

Hi Geoffrey,

The incorrect scrolling is caused by the framework itself - when you are using CollectionViewSource, there's no virtualization and several issues like the one you've found, will occur. This issue had been resolved in .Net 4.5 - you just have to make your project for this version of the framework and set VirtualizingPanel.IsVirtualizingWhenGrouping property of RadComboBox:

<telerik:RadComboBox VirtualizingPanel.IsVirtualizingWhenGrouping="True">

Hope this helps. Feel free to contact us in case you have any problems or concerns.

Regards,
Rosen Vladimirov
Telerik

 

 

[Geoffrey]

It works fine.

Thanks for your answer.

Regards,
Geoffrey