WPF DataGrid resizing problem when grouping and virtualizing

Question

WPF DataGrid has a property that allows virtualization to work with grouping: VirtualizationPanel.IsVirtualizingWhenGrouping="True". When I set it to True, I notice that columns that have star sizing, are no longer resized when the entire data grid width changes.

To reconstruct, create a new WPF app, and set the following code in MainWindow.xaml:

<Window x:Class="WpfApp1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:WpfApp1"
    mc:Ignorable="d">
<Grid>
    <DataGrid x:Name="grid" 
            CanUserResizeColumns="False"                
            AutoGenerateColumns="False"
            VirtualizingPanel.IsVirtualizingWhenGrouping="True"
            >
        <DataGrid.GroupStyle>
            <GroupStyle/>
        </DataGrid.GroupStyle>
        <DataGrid.Columns>
            <DataGridTextColumn Width="100" Header="1" Binding="{Binding .}">
            </DataGridTextColumn>
            <DataGridTextColumn Width="*" Header="2" Binding="{Binding .}">
            </DataGridTextColumn>
            <DataGridTextColumn Width="100" Header="3" Binding="{Binding .}">
            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

And the following in the MainWindow.xaml.cs:

    public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        var csv = new CollectionViewSource();
        csv.Source = new List<string>
        {
            "John", 
            "Paul", 
            "George", 
            "Ringo",
            "John",
            "Paul",
            "George",
            "Ringo",
        };

        csv.GroupDescriptions.Add(new PropertyGroupDescription("."));

        grid.ItemsSource = csv.View;
    }
}

Notice that when you resize the window, the middle column is not resized. But if you set VirtualizationPAnel.IsVirtualizingWhenGrouping="False" resizing will work as expected

Hello. I've added an answer below. Also tested with your code and it worked as you need. Could you accept the answer if it is useful? — Bulutay Saraç, Oct 01 '19 at 18:56

score 5 · Answer 1 · answered Oct 28 '19 at 11:13

<DataGrid.GroupStyle>
    <GroupStyle>
        <GroupStyle.Panel>
            <ItemsPanelTemplate>
                <DataGridRowsPresenter/>
            </ItemsPanelTemplate>
         </GroupStyle.Panel>
    </GroupStyle>
</DataGrid.GroupStyle>

Will solve your problem.

Bulutay Saraç · Answer 2 · 2019-10-28T11:12:58.510

2

I guess, GroupStyle's default PanelTemplate was breaking your design. Try this. (I've tested with your xaml codes, it worked.)

I have found this soluiton from here : https://stackoverflow.com/a/7025995/4991973

edited Oct 28 '19 at 11:12

answered Sep 16 '19 at 13:17

Bulutay Saraç

644
9
20

1

I can confirm, that in a similar constellation with both, virtualisation and dynamic columns, this fixed my Issue. The solution provided, overrides the defaul template with a very rudimentary `ItemsPanelTemplate`, that only consists of a bare `DataGridRowsPresenter`. You might want to add some `ContainerStyle` because its only a white box now. – LuckyLikey Mar 27 '20 at 14:55

WPF DataGrid resizing problem when grouping and virtualizing

2 Answers2