why not display all items in StackPanel of xaml in new line?

i want show all items as long text in StackPanel in windows phone 8. but this code show all item only in one row and other items not go to next rows. this is my code:

<StackPanel Grid.Row="0" Orientation="Horizontal" Width="300">
                                    <TextBlock Text="Id: "/>
                                    <TextBlock Text="{Binding Id}" TextWrapping="Wrap" FontWeight="Bold" FontSize="24" Foreground="GreenYellow" />
                                    <TextBlock Text=" , Adress:( " /><TextBlock Text="{Binding a3}" />
                                    <TextBlock Text=" , "/><TextBlock  Text="{Binding a2}" />
                                    <TextBlock Text=" , "/><TextBlock  Text="{Binding code}" />
                                    <TextBlock Text=" , "/><TextBlock  Text="{Binding a1"/>
                                </StackPanel>