Semantic Zoom always brings back to the first item

Question

I am trying to implement a semantic zoom in C#/Xaml for Windows 8. I succeed in displaying the zoom out and the zoom in. But when i click on item in the zoom out view I always come back to the first item of my zoom-in view.

here is how I grouped my items :

public IEnumerable<object> ListByCategory()
{
    var query = from item in listArticles.listArticles 
                orderby item.categorie
                group item by item.categorie into g
                select g;
    return query;
}

I used this to display the same collection of grouped items to the zoom out and zoom in views :

this.cvs1.Source = App.api.ListByCategory();
(semanticZoom.ZoomedOutView as ListViewBase).ItemsSource = 
    this.cvs1.View.CollectionGroups;

and my xaml code is

 <ScrollViewer
        x:Name="itemGridScrollViewer"
        AutomationProperties.AutomationId="ItemGridScrollViewer"
        Grid.Row="1"
        Margin="0,-3,0,0"
        Style="{StaticResource HorizontalScrollViewerStyle}">

<SemanticZoom x:Name="semanticZoom" VerticalAlignment="Bottom">
<SemanticZoom.ZoomedOutView>
                <GridView Foreground="Black" SelectionMode="None">
                    <GridView.ItemTemplate>
                        <DataTemplate>
                            <TextBlock
                    Text="{Binding Group.Key}"
                    FontFamily="Segoe UI Light"
                    FontSize="24" />
                        </DataTemplate>
                    </GridView.ItemTemplate>
                    <GridView.ItemsPanel>
                        <ItemsPanelTemplate>
                            <WrapGrid ItemWidth="200" ItemHeight="200" MaximumRowsOrColumns="2" 
                          VerticalChildrenAlignment="Center" />
                        </ItemsPanelTemplate>
                    </GridView.ItemsPanel>
                    <GridView.ItemContainerStyle>
                        <Style TargetType="GridViewItem">
                            <Setter Property="Margin" Value="4" />
                            <Setter Property="Padding" Value="10" />
                            <Setter Property="Background" Value="#FF25A1DB" />
                            <Setter Property="BorderThickness" Value="1" />
                            <Setter Property="HorizontalContentAlignment" Value="Left" />
                            <Setter Property="VerticalContentAlignment" Value="Bottom" />
                        </Style>
                    </GridView.ItemContainerStyle>
                </GridView>
            </SemanticZoom.ZoomedOutView>
 <SemanticZoom.ZoomedInView>
<local:MyGridView  x:Name="PicturesGridView" SelectionMode="None"
 ItemsSource="{Binding Source={StaticResource cvs1}}" IsItemClickEnabled="True"      ItemTemplate="{StaticResource CustomTileItem}" ItemClick="ItemView_ItemClick"   IsSwipeEnabled="True">
        <local:MyGridView.ItemsPanel>
            <ItemsPanelTemplate>
<VirtualizingStackPanel Orientation="Horizontal"/>
            </ItemsPanelTemplate>
        </local:MyGridView.ItemsPanel>
        <local:MyGridView.GroupStyle>
            <GroupStyle>
                <GroupStyle.HeaderTemplate>
                    <DataTemplate>
                        <Button  Click="Button_Click_1" Content="{Binding Key}" Foreground="Black" Background="White" FontSize="30" Margin="0,0,0,-10" ></Button>
                    </DataTemplate>
                </GroupStyle.HeaderTemplate>
                <GroupStyle.Panel>
                    <ItemsPanelTemplate>
<VariableSizedWrapGrid ItemWidth="75" ItemHeight="150" Orientation="Vertical" Margin="0,0,80,0" MaximumRowsOrColumns="3"/>
                    </ItemsPanelTemplate>
                </GroupStyle.Panel>
            </GroupStyle>
        </local:MyGridView.GroupStyle>
    </local:MyGridView>
</SemanticZoom.ZoomedInView>
</SemanticZoom>
    </ScrollViewer>

Thank you for your help.

What do you mean? I've never seen any implementation of a clicked method for the zoom out view in any sample code. I thought that it should automatically linked to the right group considering that it uses the same source to make the view. So when I click on an item of the zoom out it should link directly to the group which has this header. Am I wrong? — Thomas Salandre, Aug 13 '12 at 14:20
There should still be code somewhere which handles the click right? — N_A, Aug 13 '12 at 15:50
I used this tuto as an example for my code : http://msdn.microsoft.com/en-us/library/windows/apps/hh465492.aspx I can't see any click handler on it. — Thomas Salandre, Aug 14 '12 at 10:29
@mydogisbox the click handler is only 'needed' in JS versions of Win8 apps! — Depechie, Aug 14 '12 at 11:39

Depechie · Answer 1 · 2013-01-24T15:09:35.783

2

Bit difficult to see why it isn't working, so my option for you is to try working 'back' from a working solution: take a look at http://mikaelkoskinen.net/winrt-step-by-step-tutorial-mvvm-gridview-semanticzoom/ for a very good detailed example!

edited Jan 24 '13 at 15:09

answered Aug 14 '12 at 11:43

Depechie

6,102
24
46

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

I found the solution in the link that Depechie posted.

Replacing the ScrollViewer with SemanticZoom

The first and most important thing to do is to completely remove the ScrollViewer named “itemGridScrollViewer” from the Movies.xaml. The SemanticZoom control won’t work correctly if it’s inside the ScrollViewer.

Many people have problems getting the ZoomedOutView and ZoomedInView “in sync”. The usual problem is that when the item in ZoomedOutView is clicked, the ZoomedInView doesn’t scroll to the correct position. The reason for this problem usually is that the SemanticZoom –control is inside a ScrollViewer.

So effectively, I just remove the scrollViewer and it works like a charm :

 <SemanticZoom x:Name="semanticZoom" VerticalAlignment="Bottom"         
        Grid.Row="1"
        Margin="0,-3,0,0">
  <SemanticZoom.ZoomedOutView>
            <GridView Foreground="Black" SelectionMode="None">
                <GridView.ItemTemplate>
                    <DataTemplate>
                        <TextBlock
                Text="{Binding Group.Key}"
                FontFamily="Segoe UI Light"
                FontSize="24" />
                    </DataTemplate>
                </GridView.ItemTemplate>
                <GridView.ItemsPanel>
                    <ItemsPanelTemplate>
                        <WrapGrid ItemWidth="200" ItemHeight="200" MaximumRowsOrColumns="2" 
                      VerticalChildrenAlignment="Center" />
                    </ItemsPanelTemplate>
                </GridView.ItemsPanel>
                <GridView.ItemContainerStyle>
                    <Style TargetType="GridViewItem">
                        <Setter Property="Margin" Value="4" />
                        <Setter Property="Padding" Value="10" />
                        <Setter Property="Background" Value="#FF25A1DB" />
                        <Setter Property="BorderThickness" Value="1" />
                        <Setter Property="HorizontalContentAlignment" Value="Left" />
                        <Setter Property="VerticalContentAlignment" Value="Bottom" />
                    </Style>
                </GridView.ItemContainerStyle>
            </GridView>
        </SemanticZoom.ZoomedOutView>
  <SemanticZoom.ZoomedInView>
<local:MyGridView  x:Name="PicturesGridView" SelectionMode="None"
 ItemsSource="{Binding Source={StaticResource cvs1}}" IsItemClickEnabled="True"    ItemTemplate="{StaticResource CustomTileItem}" ItemClick="ItemView_ItemClick"   IsSwipeEnabled="True">
       <local:MyGridView.ItemsPanel>
        <ItemsPanelTemplate>
 <VirtualizingStackPanel Orientation="Horizontal"/>
        </ItemsPanelTemplate>
    </local:MyGridView.ItemsPanel>
    <local:MyGridView.GroupStyle>
        <GroupStyle>
            <GroupStyle.HeaderTemplate>
                <DataTemplate>
                    <Button  Click="Button_Click_1" Content="{Binding Key}" Foreground="Black" Background="White" FontSize="30" Margin="0,0,0,-10" ></Button>
                </DataTemplate>
            </GroupStyle.HeaderTemplate>
            <GroupStyle.Panel>
                <ItemsPanelTemplate>
 <VariableSizedWrapGrid ItemWidth="75" ItemHeight="150" Orientation="Vertical" Margin="0,0,80,0" MaximumRowsOrColumns="3"/>
                </ItemsPanelTemplate>
            </GroupStyle.Panel>
        </GroupStyle>
    </local:MyGridView.GroupStyle>
</local:MyGridView>
 </SemanticZoom.ZoomedInView>
</SemanticZoom>

score 0 · Answer 3 · answered Aug 14 '12 at 15:05

0

I think grouping may be the key here. Make sure your CollectionViewSource has IsSourceGrouped="True".

Also, you don't need to set

ItemsSource = this.cvs1.View.CollectionGroups;

It can be set

ItemsSource = this.cvs1;

answered Aug 14 '12 at 15:05

Jared Bienz - MSFT

3,550
17
21

Yes my CVS has IsSourceGrouped ="True" . I made it in the XAML code : . I tried to remove View.CollectionGroups and then I get an error when I arrive to this line : "Value does not fall within the expected range.". – Thomas Salandre Aug 14 '12 at 15:14
could it come from the fact that i'm not using a proper gridView in the Zoom-In View but a custom one? I don't think so because the link between two views is not supposed to be related to the view control we use, isn't it? – Thomas Salandre Aug 14 '12 at 15:19

Semantic Zoom always brings back to the first item

3 Answers3