另一个“名称'itembutton'在当前上下文中不存在”（WP8，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);