ScrollViewer scroll to specific control - windows-phone-8

Question

I have a scrollviewer with an item template on it. the user sends a control number and I need to scroll to that item. How can I find the offset for the scrollviewer?
here is the scrollviewer that I am using
<ScrollViewer Grid.Row="0" x:Name="ScrollPanel" Padding="0">
<Grid x:Name="TestPanel" >
<ItemsControl x:Name="MainItemsControl" ItemsSource="{Binding PostList}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel x:Name="PostPanel" Margin="0,5,0,5">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="60" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Image x:Name="IconUrl" Source="{Binding IconUrl}" Grid.Row="0" Grid.Column="0" Margin="12,0,12,0" VerticalAlignment="Center" HorizontalAlignment="Center" Width="50"/>
<StackPanel Grid.Row="0" Grid.Column="1">
<TextBlock x:Name="PostAuthorName" Text="{Binding PostAuthorName}" TextWrapping="NoWrap" Margin="12,0,12,0" Foreground="Black" Style="{StaticResource PhoneTextNormalStyle}"/>
<TextBlock x:Name="PostTime" Text="{Binding PostTime}" TextWrapping="NoWrap" Margin="12,0,12,0" Foreground="Black" Style="{StaticResource PhoneTextSubtleStyle}"/>
</StackPanel>
<TextBlock x:Name="ReplyNumber" Text="{Binding ReplyNumber}" Grid.Row="0" Grid.Column="2" TextWrapping="NoWrap" Foreground="Black" Margin="12,0,12,0" Style="{StaticResource PhoneTextNormalStyle}" VerticalAlignment="Center"/>
</Grid>
<RichTextBox x:Name="PostContent" localcontrols:Properties.BBCode="{Binding PostContent}" />
<Rectangle Grid.Row="1" Fill="Gray" Height="1" HorizontalAlignment="Stretch" Margin="0,10,0,10"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</ScrollViewer>

Answer 1

The offset can be calculated in this way. The code is adopted from this answer.
void ScrollToIndex(int index)
{
var itemContainer = MainItemsControl.ItemContainerGenerator.ContainerFromIndex(index) as UIElement;
GeneralTransform transform = itemContainer.TransformToVisual(ScrollPanel);
Point position = transform.Transform(new Point(0, 0));
ScrollPanel.ScrollToVerticalOffset(position.Y);
}

Answer 2

The ItemsControl does not implement logic that allows scrolling to a particular item. You can use the ListBox control instead. This control has a ScrollIntoView method that accepts the object you would like to scroll to as an argument. You can still use the RadWrapPanel by setting the ItemsPanel property of the ListBox control.
You don't have properties, but you have two methods for this: ScrollToVerticalOffset (to scroll vertically) and ScrollToHorizontalOffset (to scroll horizontally).
this.scrollViewer2.ScrollToVerticalOffset(0);