Unable to group listview alphabetically in windows 8.1 phone app just like contact list

I have following listview on my Pivot Item:

<ListView
                ItemsSource="{Binding Items}"
                IsItemClickEnabled="True"
                ContinuumNavigationTransitionInfo.ExitElementContainer="True">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Margin="0,0,0,9.5">
                            <TextBlock
                                Text="{Binding Description}"
                                TextWrapping="Wrap"
                                Pivot.SlideInAnimationGroup="1"
                                CommonNavigationTransitionInfo.IsStaggerElement="True"
                                Style="{ThemeResource ListViewItemTextBlockStyle}"
                                Margin="0,0,19,0"/>
                            <TextBlock
                                Text="{Binding Measure}"
                                TextWrapping="WrapWholeWords"
                                Pivot.SlideInAnimationGroup="2" 
                                CommonNavigationTransitionInfo.IsStaggerElement="True" 
                                Style="{ThemeResource ListViewItemContentTextBlockStyle}"
                                Margin="0,0,19,0"/>
                        </StackPanel>
                    </DataTemplate>
                </ListView.ItemTemplate>

                <ListView.GroupStyle>
                    <GroupStyle >
                        <GroupStyle.HeaderTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Description}" FontWeight="Bold" HorizontalAlignment="Center" />
                            </DataTemplate>
                        </GroupStyle.HeaderTemplate>
                    </GroupStyle>
                </ListView.GroupStyle>

But the list items are not getting grouped and it looks like:

Since I have list of size more than 1600 items so I want to group the list items alphabetically. So when I click on "A" box at the top of list view the phone takes me to view where all alphabets are shown in grid and when I click on particular alphabet phone takes me back to items in list having description starting with that alphabet. Just like contact list view.