CODEWITHSUNDEEP
windows-phone-7listbox
angela d
angela d

Reputation: 775

Index of a ListBox item from a control in the template

I have this listbox :

<ListBox x:Name="MyList" ItemsSource="{Binding ListOfBullets, Mode=TwoWay, Converter=StaticResourcedebugConverter}}">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                                <local:TaskStepControl Text="{Binding}" AddHnadler="{Binding DelegateForHandlingAddTaskStep, ElementName=uc}"></local:TaskStepControl>                          
                        </DataTemplate>
                    </ListBox.ItemTemplate>
</ListBox>

The bindings work ok. Each local:TaskStepControl has an Add button , which is connected to AddHnadler. AddHnadler looks like this :

void AddHnadler(TaskStepControl theControl)
{
   // "theControl" --> this TaskStepControl on which the Add button was pressed
   //In here I want to get the index of "theControl" in the ListBox "MyList". 
   //I've tried

   var pos = MyList.Items.IndexOf(theControl);

   //pos == -1  always  
}

I can not use the SelectionChanged event because the Add button on each TaskStepControl wont pass the Click event to the ListBox.

I usually work in the code behind not in xaml , so this may be very simple but I can't get it to work. I need something as simple as "IndexOf" , no MVVM stuff , as I said I usually work in the code behind not in xaml, just this time I have to implement this.

Thank you!

Upvotes: 1

Views: 964

Answers (1)

Richard Szalay
Richard Szalay

Reputation: 84724

The ListBox works with two lists: items (from ItemsSource) and the ListItemContainer (the control container).

Your TaskStepControl is a child of the ListItemContainer and therefore available in neither list. For your purposes, I'd take advantage of the fact that DataContext (and list item) is inherited to your TaskStepControl:

// FYI: 'Hnadler' was a typo here
void AddHandler(TaskStepControl theControl)
{
   object listItem = theControl.DataContext;

   var itemContainerGenerator = MyList.ItemContainerGenerator;

   DependencyObject itemContainer = itemContainerGenerator.ContainerFromItem(listItem);

   int pos = itemContainerGenerator.IndexFromContainer(itemContainer);
}

Upvotes: 2

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