Reloading listbox in WP7 - windows-phone-7

Question

I am using List to bind a listbox which is as follows:
<ListBox x:Name="ContentPanel" SelectionChanged="onSelectionChanged" Background="LightGray" Grid.Row="2">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Name="{Binding title}" Height="165" Margin="25,5,25,0" Width="430">
<Border BorderThickness="1" Height="165" BorderBrush="Gray">
<toolkit:ContextMenuService.ContextMenu >
<toolkit:ContextMenu IsZoomEnabled="False">
<toolkit:MenuItem Name="Delete" Header="Delete Message" Click="DeleteMessage_Click" >
</toolkit:MenuItem>
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<StackPanel Orientation="Vertical">
<StackPanel>
<TextBlock Text="{Binding title}" Margin="5,0,0,0" FontSize="25" Foreground="Black"/>
<TextBlock Text="{Binding msgFrom}" Padding="5" TextWrapping="Wrap" Foreground="Gray" FontSize="20"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock Margin="5,13,0,0" FontSize="24" Foreground="WhiteSmoke" Text="{Binding msgReceivedOn}"/>
<toolkit:ToggleSwitch Margin="170,10,0,0" IsChecked="{Binding msgStatus}" Unchecked="UnChecked" Background="LightBlue" Checked="Checked"/>
</StackPanel>
</StackPanel>
</Border>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
At first data is successfully loaded. But when I use the Contextmenu to remove the item and reload the listbox.. it fires an exception. Code to handle the context menu click is:
private void DeleteMessage_Click(object sender, RoutedEventArgs e)
{
MenuItem item = sender as MenuItem;
Message message = (Message)item.DataContext;
MessageBoxResult result = MessageBox.Show("Are you sure to delete the message??", "Confirmation", MessageBoxButton.OKCancel);
if (result == MessageBoxResult.Cancel)
return;
else
{
ContentPanel.Items.Remove(message);
lstMessage.Remove(message);
}
ContentPanel.ItemSource = lstMessage;
}
But it this code is not working. So any suggestions?

Answer 1

You don't need each time to bind collection to a list. Also, when you remove an item from your collection, it should disappear also in the list (if binding setup properly). I think you have not ObservableCollection, so you need manage items manually. Please, consider to use ObservableCollection.
Your code should looks like:
lstMessage.Remove(message); //it must raises CollectionChanged event automatically
And this lines is unnecessary:
ContentPanel.Items.Remove(message);
ContentPanel.ItemSource = lstMessage;