I have a listbox with ~20 items.If orientation is portait the margin of the grid must be "140,25,5,0" and width of stackpanel inside 320 If orientation is landscape margin must be "350,25,5,0" and width of stackpanel is 450.How I can change it dinamically such as conversation view in WP7?
<Grid x:Name="LayoutRoot" >
<ListBox ScrollViewer.VerticalScrollBarVisibility="Disabled" x:Name="listmy">
<ListBox.ItemTemplate>
<DataTemplate>
<local:TypeMessage Content="{Binding}">
<local:TypeMessage.Me>
<DataTemplate>
<Grid HorizontalAlignment="Right" Margin="350,25,5,0">
<TextBlock HorizontalAlignment="Right" Margin="0,-25,30,0" TextWrapping="Wrap" Text="Вы" VerticalAlignment="Top"/>
<StackPanel Background="{StaticResource PhoneAccentBrush}" Width="320">
<TextBlock TextWrapping="Wrap" Foreground="{Binding read_state, Converter={StaticResource ReadConverter}}" Text="{Binding text}" Margin="5,3" />
<TextBlock Text="{Binding date_time}" TextAlignment="Right" Margin="5,0"/>
</StackPanel>
<Path Data="m 0,0 l 16,0 l 0,16 l -16,-16"
Fill="{StaticResource PhoneAccentBrush}"
HorizontalAlignment="Right" UseLayoutRounding="False" d:LayoutOverrides="VerticalAlignment, GridBox" Height="16" VerticalAlignment="Top" Margin="0,-15.167,8.757,0" RenderTransformOrigin="0.5,0.5">
<Path.RenderTransform>
<CompositeTransform Rotation="91.157"/>
</Path.RenderTransform>
</Path>
</Grid>
</DataTemplate>
</local:TypeMessage.Me>
<local:TypeMessage.You>
<DataTemplate>
<Grid Margin="5,25,30,0" >
<Path Data="m 0,0 l 0,16 l 16,0 l -16,-16"
Fill="{StaticResource PhoneAccentBrush}"
Margin="9.5,-16,0,0" UseLayoutRounding="False" Height="16" VerticalAlignment="Top" d:LayoutOverrides="VerticalAlignment" HorizontalAlignment="Left"/>
<StackPanel Background="{StaticResource PhoneAccentBrush}" Width="320">
<TextBlock TextWrapping="Wrap" Foreground="{Binding read_state,Converter={StaticResource ReadConverter}}" Text="{Binding text}" />
<TextBlock TextAlignment="Right" Text="{Binding date_time}" />
</StackPanel>
<TextBlock HorizontalAlignment="Left" Margin="28,-27,0,0" TextWrapping="Wrap" Text="{Binding author_name}" VerticalAlignment="Top"/>
</Grid>
</DataTemplate>
</local:TypeMessage.You>
</local:TypeMessage>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>