RadGridView gets empty when I use CollectionViesSource with different classes

[Roman]

RadGridView gets empty when I use CollectionViesSource with different inherited classes. Here is the example:

I created following window:

<Window x:Class="WpfApplication6.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <CollectionViewSource Source="{Binding Source={x:Static Application.Current}, Path=Employees}" x:Key="employees"/>
    </Window.Resources>
    <Grid>
        <telerik:RadGridView ItemsSource="{Binding Source={StaticResource employees}}" Margin="12,12,0,120" />
        <ListBox ItemsSource="{Binding Source={StaticResource employees}}" Margin="12" Height="102" VerticalAlignment="Bottom" >
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding Name}" Margin="8" />
                        <TextBlock Text="{Binding Id}" Margin="8"  />
                        <TextBlock Text="{Binding Class}" Margin="8"  />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

And codebehind:

namespace WpfApplication6
{
    public partial class App : Application
    {
        public ObservableCollection<Employee> Employees { get; set; }

        private void Application_Startup(object sender, StartupEventArgs e)
        {
            Employees = new ObservableCollection<Employee>();
            Employees.Add(new Employee() { Name = "Alice", Id = 1 });
            Employees.Add(new Employee() { Name = "Bob", Id = 2 });
            Employees.Add(new Employee() { Name = "Charlie", Id = 3 });
            new MainWindow().Show();
        }
    }

    public class Employee
    {
        public string Name { get; set; }
        public int Id { get; set; }
        public virtual string Class { get { return "Base"; } }
    }

    public class ExtendedEmployee : Employee
    {
        public override string Class { get { return "Extended"; } }
    }
}

In this example everything is ok, RadGridView and ListView displays same results. In following example everything is ok too:

Employees.Add(new ExtendedEmployee() { Name = "Alice", Id = 1 });
Employees.Add(new ExtendedEmployee() { Name = "Bob", Id = 2 });
Employees.Add(new ExtendedEmployee() { Name = "Charlie", Id = 3 });

But if I'll use mixed collection RadGridView become empty and ListBox will display correct results:

Employees.Add(new Employee() { Name = "Alice", Id = 1 });
Employees.Add(new Employee() { Name = "Bob", Id = 2 });
Employees.Add(new ExtendedEmployee() { Name = "Charlie", Id = 3 });

Screenshot is attached.
What's the problem here?

[Vanya Pavlova]

Hi Roman,

This is really strange issue and we need some time to investigate it.
As a quick workaround you can define a CellTemplate in any of your RadGridView columns with a TextBlock bound to a particular property.

I have prepared an example for you that demonstrates this approach and also an alternative without CollectionViewSource usage that does the same thing.

Please see the attached project and let me know how this works for you.

Regards,
Vanya Pavlova
the Telerik team

[Roman]

Yes, that works. For now I'll stick with solution without CollectionViewSource. But It'll be good if you'll fix that issue in future updates.

[Matthias]

Same Problem here :(

Any progress with this bug?

Regards,
Matthias

[Matthias]

I just had a look at the provided solutions.

Using CellTemplates seems to be a fix at first glance, but sorting and grouping is not possible this way.

The second solution has no custom sorting or filtering logic.

At the moment the only solution seems to be to keep 2 collections, one with all items and one with only the filtered items.

Do you have any other/better ideas?

Regards, Matthias

[Dimitrina]

Hello Matthias,

 This issue has been fixed for the Q2 2011 release of the RadControls.

Greetings,
Didie
the Telerik team