Question

I have 2 different group page with 2 look alike classes which using the same technique

This for 1st group page named as NewsFeed

<!-- Collection of grouped items displayed by this page -->
<CollectionViewSource x:Name="groupedItemsViewSource" Source="{Binding Groups}" IsSourceGrouped="true"
    ItemsPath="Items" d:Source="{Binding ItemGroups, Source={d:DesignInstance Type=data:NewsFeedDataSource, IsDesignTimeCreatable=True}}"/>

to pass the group data into the group page.

This for 2nd group page named as Event

<CollectionViewSource x:Name="groupedItemsViewSource" Source="{Binding Groups}" IsSourceGrouped="true"
    ItemsPath="Items" d:Source="{Binding ItemGroups, Source={d:DesignInstance Type=data:EventDataSource, IsDesignTimeCreatable=True}}"/>

and some of the code sample which binding with the ViewSource above

 <GridView x:Name="itemGridView" AutomationProperties.AutomationId="ItemGridView" AutomationProperties.Name="Grouped Items" Margin="116,0,40,46"
                ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}" ItemTemplate="{StaticResource Standard250x250ItemTemplate}"
                SelectionMode="None"
                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"
                                        Content="{Binding Title}"
                                        Click="Header_Click"
                                        Style="{StaticResource TextButtonStyle}"/>
                                        </Grid>
                                    </DataTemplate>
                                </GroupStyle.HeaderTemplate>

                                <GroupStyle.Panel>
                                    <ItemsPanelTemplate>
                                        <VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
                                    </ItemsPanelTemplate>
                                </GroupStyle.Panel>
                            </GroupStyle>
                        </GridView.GroupStyle>
                    </GridView>

and the static resources which binding to 250×250 template code will be

<DataTemplate x:Key="Standard250x250ItemTemplate">
    <Grid HorizontalAlignment="Left" Width="250" Height="250">
        <Border Background="{StaticResource ListViewItemPlaceholderRectBrush}">
            <Image Source="{Binding Image}" Stretch="UniformToFill"/>
        </Border>
        <StackPanel VerticalAlignment="Bottom" Background="{StaticResource ListViewItemOverlayBackgroundBrush}">
            <TextBlock Text="{Binding Title}" Foreground="{StaticResource ListViewItemOverlayTextBrush}" Style="{StaticResource TitleTextStyle}" Height="60" Margin="15,0,15,0"/>
            <TextBlock Text="{Binding PublishDate}" Foreground="{StaticResource ListViewItemOverlaySecondaryTextBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>
        </StackPanel>
    </Grid>
</DataTemplate>

Even that the whole app able to work well. But i found there is a line bottom of either 1 source code above. The blue line show tat the object does not match target type.

Anyone knw wat happening to the code? =D
Sorry if i didn’t post up all information. Is kinda big. Please request if require more info.

Answer 1

After few more testing, i found that this problem caused due to the same name for itemspath and d:Source.
The code should as least look like

   <UserControl.Resources>

        <CollectionViewSource x:Name="groupedItemsViewSource" Source="{Binding Groups}" IsSourceGrouped="true"
            ItemsPath="EventItems" d:Source="{Binding EventItemGroups, Source={d:DesignInstance Type=data:EventDataSource, IsDesignTimeCreatable=True}}"/>
    </UserControl.Resources>

and

<UserControl.Resources>

    <!-- Collection of grouped items displayed by this page -->
    <CollectionViewSource x:Name="groupedItemsViewSource" Source="{Binding Groups}" IsSourceGrouped="true"
        ItemsPath="Items" d:Source="{Binding ItemGroups, Source={d:DesignInstance Type=data:NewsFeedDataSource, IsDesignTimeCreatable=True}}"/>
</UserControl.Resources>