LongListSelector Windows Phone 8.1 - windows

Question

I wanted to Develop a similar layout like Longlist Selector Wp8 in Windows phone 8.1.
I came across a issue, my list is not appearing.
XAML page
<Grid >
<Grid.Resources>
<CollectionViewSource x:Name="MainGrps"
IsSourceGrouped="True"/>
</Grid.Resources>
<ListView ItemsSource="{Binding Source={StaticResource MainGrps}}" Margin="50">
<ListView.ItemTemplate>
<DataTemplate >
<Grid Background="Gray">
<StackPanel>
<TextBlock Foreground="White" FontSize="20" Text="{Binding ItmName}"/>
<TextBlock Foreground="White" FontSize="20" Text="{Binding ItmType}"/>
</StackPanel>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.GroupStyle>
<GroupStyle HidesIfEmpty="True" >
<GroupStyle.HeaderTemplate>
<DataTemplate >
<Grid Background="Red">
<StackPanel Orientation="Horizontal" >
<TextBlock Text="{Binding GrpItmName}" Foreground="White"/>
<TextBlock Text="{Binding ItemsCount}" Foreground="White"/>
</StackPanel>
</Grid>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
</Grid>
Code Behind:
private void OnPageLoaded(object sender, RoutedEventArgs e)
{
lst_grp = new List<Grp>();
for (int i = 0; i < 10; i++)
{
Grp grp = new Grp();
grp.GrpItmName = "grp name " + i;
grp.ItemsCount = i;
grp.LstItms = new List<Itm>();
Itm itm = new Itm();
itm.ItmName = "itm name " + i;
itm.ItmType = "itm type " + i;
grp.LstItms.Add(itm);
grp.LstItms.Add(itm);
grp.LstItms.Add(itm);
lst_grp.Add(grp);
}
this.MainGrps.Source = lst_grp;
}
Is there any problem with above code?
Please help me to figure it out or suggest if you have working code.

Answer 1

Change
<GroupStyle HidesIfEmpty="True" >
to:
<GroupStyle HidesIfEmpty="False" >

Answer 2

Try to add this in the XAML inside the ListView tag:
HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
Or try to set the width and the height parameter of the ListView manually.. Just to try..
Let me know!