Another "The name 'itembutton' does not exist in the current context" (WP8, XAML) - xaml

Question

I know that this question has been posted about a thousand times, but I did not find a solution that solved my problem.
I've got a LongListSelector with this ItemTemplate:
<DataTemplate x:Key="AddrBookItemTemplate">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock FontWeight="Bold" Text="{Binding Name}" HorizontalAlignment="Stretch" VerticalAlignment="Center" Grid.Column="0" Grid.Row="0" />
<Button x:Name="itembutton" CommandParameter="{Binding ItemID}" Content="{Binding ButtonCaption}" Width="150" HorizontalAlignment="Right" Grid.Column="1" Grid.Row="0" Click="ItemButtonClick"/>
</Grid>
</DataTemplate>
So what happens is simply that I get this beautiful error message that I posted in the title. And I do not have a clue, why?!
private void ItemButtonClick(object sender, RoutedEventArgs e)
{
if (sender == this.itemButton) {
....

Answer 1

From the DataTemplate it looks like you're showing this button in a container like a ListBox or LongListSelector.
That means that there isn't an itembutton in this scope (presumably this is either UserControl or PhoneApplicationPage): there is in fact one for each of your ListBoxItems!
You'll have to find another way of finding your button.
Update:
You should find that the DataContext of your button matches the item of the list it is contained in. That's probably the easiest way of proceeding: however if all else fails you can use the Tag property as you suggest.
Like:
private void ItemButtonClick(object sender, RoutedEventArgs e)
{
var theButton = (Button) sender;
var myItem = (TypeOfAnObjectInMyList) theButton.DataContext;
doSomethingWithMyItem(myItem);