XAML datagrid datatemplate - xaml

Question

I'm going through the Windows 8 Bing Translator Walkthrough
I was able to follow everything except the XAML part. I'm very new to XAML. Below is what the walkthrough appears to recommend, however VS2012 indicated the markup is invalid, and the error displayed says "the property "content" is set more than once". Is this the only issue? Where this is set more than once?
<GridView ItemTemplate="{StaticResource TweetTemplate}" SelectionMode="None" ItemsSource="{Binding tweets}"></GridView>
<DataTemplate x:Key="TweetTemplate">
<Grid>
<Rectangle Fill="#FFDA713F" HorizontalAlignment="Left" Height="115" Margin="10,11,0,0"
VerticalAlignment="Top" Width="455" RadiusX="20" RadiusY="20"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="50"
Margin="176,12,0,0" TextWrapping="Wrap" x:Name="txtTweet"
Text="{Binding Title}" VerticalAlignment="Top" Width="277" FontSize="12"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="50"
Margin="176,72,0,0" TextWrapping="Wrap" x:Name="txtTrans"
Text="{Binding translatedText}" VerticalAlignment="Top" Width="277"
FontSize="12"/>
<Image Source="{Binding ImageUri}" HorizontalAlignment="Left" Height="89"
Margin="20,20,0,0" VerticalAlignment="Top" Width="116"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="17"
Margin="24,109,0,0" TextWrapping="Wrap" Text="{Binding Author}"
VerticalAlignment="Top" Width="150" FontSize="10"/>
</Grid>
</DataTemplate>

Answer 1

...and no sooner do I post the question, I find the answer. the above needs to be arranged as follows:
Note that from the example in the link provided above the author used RefreshAppBarButtonStyle. This was changed to AppBarButtonStyle. I;m not sure I fully understand the xaml page yet, but at least I have a working framework to diagnose.
<Page.Resources>
<DataTemplate x:Key="TweetTemplate">
<Grid>
<Rectangle Fill="#FFDA713F" HorizontalAlignment="Left" Height="115" Margin="10,11,0,0" VerticalAlignment="Top" Width="455" RadiusX="20" RadiusY="20"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="50" Margin="176,12,0,0" TextWrapping="Wrap" x:Name="txtTweet" Text="{Binding Title}" VerticalAlignment="Top" Width="277" FontSize="12"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="50" Margin="176,72,0,0" TextWrapping="Wrap" x:Name="txtTrans" Text="{Binding translatedText}" VerticalAlignment="Top" Width="277" FontSize="12"/>
<Image Source="{Binding ImageUri}" HorizontalAlignment="Left" Height="89" Margin="20,20,0,0" VerticalAlignment="Top" Width="116"/>
<TextBlock Foreground="White" HorizontalAlignment="Left" Height="17" Margin="24,109,0,0" TextWrapping="Wrap" Text="{Binding Author}" VerticalAlignment="Top" Width="150" FontSize="10"/>
</Grid>
</DataTemplate>
</Page.Resources>
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<GridView ItemTemplate="{StaticResource TweetTemplate}" SelectionMode="None" ItemsSource="{Binding tweets}"></GridView>
</Grid>
<Page.BottomAppBar>
<AppBar x:Name="bottomAppBar" Padding="10,0,10,0">
<Grid>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
<TextBlock x:Name="txtPrompt" Text="Search Term: " Height="24" FontSize="24"></TextBlock>
<TextBox x:Name="txtSearchTerm" Width="300" Height="24"></TextBox>
<Button Style="{StaticResource AppBarButtonStyle}" Click="Button_Click_1" />
</StackPanel>
</Grid>
</AppBar>
</Page.BottomAppBar>
Hope this is also of use to someone else.
Paul