在LongListSelector中获取选定的索引

Question

I'm using a LongListSelector for a WP8 app. I searched on several websites but did not found if there was a way to know the index of the item the user taped in the List. If anyone has an idea, it would be nice. Thanks

`

        <phone:LongListSelector x:Name="ListeNotes" Height="535" Width="426" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="36" Margin="54,0,0,0">

            <phone:LongListSelector.ItemTemplate>
                <DataTemplate>

                    <TextBlock Text="{Binding Titre}"/>

                </DataTemplate>

            </phone:LongListSelector.ItemTemplate>

        </phone:LongListSelector>

`

Answer 1

I'd create in code-beind or ViewModel (depending on what are you using), public variable

Public Int32 itemSelectedIndex {get;set;} //This is a public variable, therefore add it inside your class

and bind it to SelectedIndex as following:

<phone:LongListSelector x:Name="ListeNotes" Height="535" Width="426" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="36" Margin="54,0,0,0" SelectedIndex ="{Binding itemSelectedIndex, UpdateSourceTrigger = PropertyChanged}">

don't forget to add datacontext reference in code behind

Public void MainWindow()
{
InitializeComponents();
this.DataContext = this;//this makes sure that you can bind public varibles to XAML
}

Afterwards you simply reference itemSelectedIndex anywhere in your code and it will return selected value (eg System.Windows.MessageBox.Show(itemSelectedIndex.ToString());

Answer 2

In the handler:

SelectionChanged(sender As Object, e As SelectionChangedEventArgs) Handles ListeNotes.SelectionChanged`

The "sender" is the ListBox . So all you have to do is cast "sender" to ListBox , and use its SelectedIndex property.

Dim listBox As ListBox = CType(sender, ListBox)
Dim tappedIndex = listBox.SelectedIndex

Answer 3

你可以通过

Dim num As Integer = (sender as LonglistSelector).Datasource.IndexOf((sender as LonglistSelector).SelectedItem)

Answer 4

找不到解决方案...实际上，我只是说用户不能拥有相同的Note对象两次，并且我在List（Of Note）中使用IndexOf方法来获取LongListSelector中SelectedItem的索引。