WinRT GridView Stacking - windows-runtime

Question

In the default application there is a gridview that displays groups of data stacked on top of each other (2 boxes high for each group).
When I implement my grid view it doesn't stack. It is just 1 horizontal list.
I've compared my GridView to the default application and it appears to be VERY SIMILAR. Is there a command I'm missing or do I have to setup my data differently?
Any help is appreciated.
My GridView:
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="vehicleGridView"
AutomationProperties.Name="vehicles"
TabIndex="1"
Grid.Row="1"
Margin="83,0,-83,-4"
Padding="116,0,116,46"
ItemsSource="{Binding vehicles}"
ItemTemplate="{StaticResource Standard250x250ItemTemplate}"
SelectionMode="None"
IsItemClickEnabled="True"
ItemClick ="vehicleClick">
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Grid Margin="1,0,0,6">
<Button
AutomationProperties.Name="VehicleMake"
Content="{Binding VehicleMake}"
Style="{StaticResource TextPrimaryButtonStyle}"/>
</Grid>
</DataTemplate>
</GroupStyle.HeaderTemplate>
<GroupStyle.Panel>
<ItemsPanelTemplate>
<VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
</ItemsPanelTemplate>
</GroupStyle.Panel>
</GroupStyle>
</GridView.GroupStyle>
</GridView>
Default Example:
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemGridView"
AutomationProperties.Name="Grouped Items"
Grid.RowSpan="2"
Padding="116,137,40,46"
ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"
ItemTemplate="{StaticResource Standard250x250ItemTemplate}"
SelectionMode="None"
IsSwipeEnabled="false"
IsItemClickEnabled="True"
ItemClick="ItemView_ItemClick">
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Grid Margin="1,0,0,6">
<Button
AutomationProperties.Name="Group Title"
Click="Header_Click"
Style="{StaticResource TextPrimaryButtonStyle}" >
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Title}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" />
<TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-7,0,10" Style="{StaticResource GroupHeaderTextStyle}"/>
</StackPanel>
</Button>
</Grid>
</DataTemplate>
</GroupStyle.HeaderTemplate>
<GroupStyle.Panel>
<ItemsPanelTemplate>
<VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
</ItemsPanelTemplate>
</GroupStyle.Panel>
</GroupStyle>
</GridView.GroupStyle>
</GridView>

Answer 1

You need to use WrapGrid in your ItemsPanelTemplate. Try this.
<ItemsPanelTemplate><WrapGrid /></ItemsPanelTemplate>