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C# WinUI3 Desktop: How can I reference or control a button in a ListView's selected item DataTemplate?

I have a ListView:
<ListView x:Name="All_Staging_ListView"
SelectionMode="Single"
SelectionChanged="All_Staging_ListView_SelectionChanged"
ItemTemplate="{StaticResource All_Staging_ListView_Template}"
BorderThickness="3"
BorderBrush="#005986"
HorizontalAlignment="Stretch"/>
I have a DataTemplate for the ListView:
<Page.Resources>
<DataTemplate x:Key="All_Staging_ListView_Template" x:DataType="local1:All_Staging_Data_Collection_ViewEdit">
<Border BorderBrush="Aqua" BorderThickness="1" Padding="5" Margin="5">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="100"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{x:Bind Metric_ID}" x:Phase="1" FontWeight="ExtraBold" Margin="0,0,5,0"/>
<TextBlock Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2" Text="{x:Bind Period}" Margin="0,0,0,0"/>
<TextBlock Grid.Row="0" Grid.Column="3" Text="{x:Bind ID}" Margin="25,0,0,0"/>
<Button Grid.Row="0" Grid.RowSpan="2" Grid.Column="4" x:Name="ButtonListViewEdit" Content="Edit this metric" Margin="20,0,0,0" Visibility="Collapsed" Click="ButtonListViewEdit_Click"/>
<TextBlock Grid.Row="1" Grid.Column="0" Text="Name:" FontWeight="Bold" />
<TextBlock Grid.Row="1" Grid.Column="1" Text="{x:Bind Metric_Name}" x:Phase="1" Margin="0,0,20,0"/>
<TextBlock Grid.Row="1" Grid.Column="2" Text="Product:" FontWeight="Bold"/>
<TextBlock Grid.Row="1" Grid.Column="3" Text="{x:Bind Product}"/>
<TextBlock Grid.Row="2" Grid.Column="0" Text="Definition:" FontWeight="Bold"/>
<TextBlock Grid.Row="2" Grid.Column="1" Text="{x:Bind Metric_Definition}" x:Phase="1" Margin="0,0,20,0"/>
<TextBlock Grid.Row="2" Grid.Column="2" Text="Company:" FontWeight="Bold" />
<TextBlock Grid.Row="2" Grid.Column="3" Text="{x:Bind Company}"/>
<TextBlock Grid.Row="3" Grid.Column="0" Text="Goal:" FontWeight="Bold"/>
<TextBlock Grid.Row="3" Grid.Column="1" Text="{x:Bind Goal_Description}" x:Phase="1" Margin="0,0,20,0"/>
<TextBlock Grid.Row="3" Grid.Column="2" Text="System:" FontWeight="Bold"/>
<TextBlock Grid.Row="3" Grid.Column="3" Text="{x:Bind System}"/>
</Grid>
</Border>
</DataTemplate>
</Page.Resources>
When an item in the ListView is 'selected' I would like to make the button 'ButtonListViewEdit' visible!!!!! Edit: (I would like to make the button in the selected item visible only, not in the other unselected items in the ListView).
I don't know the syntax to reference the button within the datatemplate in the 'SelectionChanged' event handler:
private void All_Staging_ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
All_Staging_Data_Collection_ViewEdit listitem = new All_Staging_Data_Collection_ViewEdit();
listitem = (All_Staging_Data_Collection_ViewEdit)All_Staging_ListView.SelectedItem;
Debug.WriteLine($"ListView > SelectionChanged > Metric ID: {listitem.Metric_ID}");
}
I am able to access the values of the bound textblocks, but not the button (to make it visible).
Thank you members of stackoverflow for you help in advance.

Bind the Visibility property of the Button to a property of your All_Staging_Data_Collection_ViewEdit class or get a reference to the Button using the VisualTreeHelper class in your event handler:
private void All_Staging_ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
foreach (object selectedItem in e.AddedItems)
DisplayOrHideButton(selectedItem, true);
foreach (object selectedItem in e.RemovedItems)
DisplayOrHideButton(selectedItem, false);
}
private void DisplayOrHideButton(object item, bool display)
{
ListViewItem container = All_Staging_ListView.ContainerFromItem(item) as ListViewItem;
if (container != null)
{
Button button = FindVisualChild<Button>(container);
if (button != null)
button.Visibility = display ? Visibility.Visible : Visibility.Collapsed;
}
}
private static T FindVisualChild<T>(DependencyObject obj) where T : DependencyObject
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
if (child != null && child is T t)
return t;
else
{
T childOfChild = FindVisualChild<T>(child);
if (childOfChild != null)
return childOfChild;
}
}
return null;
}

WPF ListView - detect ListVewItem when selected item is not clicked

I'm trying to get an item in ListView in WPF when user doesn't select an item by clicking on it but the user taps on it.
Is there a way to achieve this in WPF ListView.
ListView dataSource is filled by a dynamic collection in code-behind.
I'm getting a null object when user taps on it.
Item selectedItem = (Item)lv_CartItems.SelectedItem;
this is how my data-template looks like for listview.
<ListView.ItemTemplate>
<DataTemplate>
<Viewbox>
<Grid Width="230" Height="110" >
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width=".1*" />
<ColumnDefinition />
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition Width=".5*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="2*" />
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Border BorderBrush="LightGray" BorderThickness="1"
Grid.Row="0" Grid.Column="0"
Grid.ColumnSpan="6" Grid.RowSpan="3" >
</Border>
<Viewbox Grid.Row="0" >
<Image Name="img_ItemImage"
Source="{Binding Image, Mode=TwoWay }"
Width="20" Height=" 25" />
</Viewbox>
<Viewbox Grid.Column="2" Grid.ColumnSpan="3" VerticalAlignment="Top" >
<TextBlock Name="lbl_ItemName" TextWrapping="Wrap" Width="180" Foreground="Gray"
Text="{Binding Name , Mode=TwoWay }" Tag="{Binding SKU_No,Mode=TwoWay}" >
</TextBlock>
</Viewbox>
<Viewbox Grid.Row="1" Margin="10,0" VerticalAlignment="Top" >
<TextBlock Foreground="Gray" >Qty:</TextBlock>
</Viewbox>
<Viewbox Grid.Row="2" Margin="0,0" VerticalAlignment="Top" >
<StackPanel Orientation="Horizontal" >
<Button Name="btn_Minus" FontWeight="ExtraBold" Padding="0" Width="12"
Resources="{StaticResource cartitembutton}" Click="btn_Minus_Click" >
<Image Source="/Resources\Icons\minus.png" ></Image>
</Button>
<Border BorderThickness="1" Margin="2,0" Width="13" CornerRadius="2" BorderBrush="LightGray" >
<TextBlock Name="lbl_Quantity" FontWeight="Bold" Foreground="Gray"
HorizontalAlignment="Center" VerticalAlignment="Center"
Text="{Binding Quantity , Mode=TwoWay }">
</TextBlock>
</Border>
<Button Name="btn_Increment" FontWeight="ExtraBold" Width="12"
Resources="{StaticResource cartitembutton}"
Padding="0"
Click="btn_Increment_Click">
<Image Source="/Resources\Icons\union_10.png" ></Image>
</Button>
</StackPanel>
</Viewbox>
<Viewbox Grid.Row="1" Grid.Column="2" Margin="5,0"
HorizontalAlignment="Left" Grid.ColumnSpan="3" >
<TextBlock Name="lbl_Price" FontWeight="DemiBold"
Text="{Binding Price , Mode=TwoWay}" ></TextBlock>
</Viewbox>
<Viewbox Grid.Row="2" Grid.Column="2" Grid.ColumnSpan="3"
VerticalAlignment="Top" Margin="0,0" >
<TextBlock Name="lbl_Appearence"
Text="{Binding Appearance , Mode=TwoWay }"
TextWrapping="Wrap" Foreground="Gray" Width="210" >
</TextBlock>
</Viewbox>
<Viewbox Grid.Column="5" HorizontalAlignment="Center" VerticalAlignment="Top" Margin="2,2"
>
<Button Name="btn_DeleteItem"
Click="btn_DeleteItem_Click"
Resources="{StaticResource cartitembutton}" >
<Image Source="/Resources/Icons/delete.png" ></Image>
</Button>
</Viewbox>
</Grid>
</Viewbox>
</DataTemplate>
</ListView.ItemTemplate>

You should use data binding to retrieve the selected item. The source property will be automatically updated when the ListView.SelectedItem changes.
Touch is handled the same way as click is handled. The framework converts touch events to mouse events.
I noticed that you wrapped every element into a ViewBox. That is not necessary and will only degrade performance. When the elements are hosted inside a Grid they will resize automatically by default. Exceptions are elements that need an initial size like Shape or Image. But since the item containers won't resize themselves, the content of the containers won't resize too.
To force all elements to occupy max horizontal space you can set a Style that targets the item container:
<ListView.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="HorizontalContentAlignment"
Value="Stretch" />
</Style>
</ListView.ItemContainerStyle>
MainWindow.xaml.cs
public partial class MainWindow : Window
{
public static readonly DependencyProperty ItemsProperty = DependencyProperty.Register(
"Items",
typeof(ObservableCollection<Item>),
typeof(MainWindow),
new PropertyMetadata(default(ObservableCollection<Item>)));
public ObservableCollection<Item> Items
{
get => (ObservableCollection<Item>) GetValue(MainWindow.ItemsProperty);
set => SetValue(MainWindow.ItemsProperty, value);
}
public static readonly DependencyProperty SelectedItemProperty = DependencyProperty.Register(
"SelectedItem",
typeof(Item),
typeof(MainWindow),
new PropertyMetadata(default(Item), MainWindow.OnSelectedItemChanged));
public Item SelectedItem
{
get => (Item) GetValue(MainWindow.SelectedItemProperty);
set => SetValue(MainWindow.SelectedItemProperty, value);
}
public MainWindow()
{
InitializeComponent();
this.DataContext = this;
this.Items = new ObservableCollection<Item>();
// Initialize data source
CreateItems();
}
// Property changed callback of the SelectedItem property
private static void OnSelectedItemChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
// Reference to instance members in a class scope
var _this = d as MainWindow;
if (e.NewValue is ItemCollection selectedItem)
{
// Handle currently selected item
}
}
}
MainWindow.xaml
<Window>
<ListView ItemsSource="{Binding Items}"
SelectedItem="{Binding SelectedItem}" />
</Window>

How to access a specific item in itemscontrol and retrieve some data in UWP

I have an ItemsControl with DataTemplate in my Page.Xaml and the code is like below:
<ItemsControl x:Name="chatUI" VerticalAlignment="Bottom">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid x:Name="myGrid" Width="340" Background="{Binding Background}" HorizontalAlignment="{Binding GridHorizontalAlign}" Margin="10,0,10,10" MinHeight="45" BorderBrush="#FF003A4F" BorderThickness="0,0,0,2">
<Polygon Visibility="{Binding RightVisibility}" Fill="{Binding Background}" Points="0,0 5,6, 0,12" VerticalAlignment="Top" HorizontalAlignment="Right" Margin="0,0,-5,0" />
<Polygon Visibility="{Binding LeftVisibility}" Fill="{Binding Background}" Points="5,0 0,6, 5,12" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="-5,0,0,0" />
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Text="{Binding Text}" TextWrapping="Wrap" FontSize="15" FontFamily="Segoe UI" Foreground="White" Margin="10,10,10,0"/>
<TextBlock Grid.Row="1" Text="{Binding Time}" TextWrapping="Wrap" FontSize="11" FontFamily="Segoe UI" Foreground="LightGray" Margin="10,0,10,5" VerticalAlignment="Bottom" TextAlignment="Right"/>
</Grid>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
What I need right now is getting Text which is bound to the TextBlock when I right click on the grid named myGrid. How is that possible in C#?

We can add the RightTapped event of the Grid, it will be fired when you right click the Grid.
In the RightTapped event we can use Grid.Children to get the collection of child elements of the Grid. That we can get the Grid in the root Grid that named myGrid. That we can use the Grid.Children to get the TextBlock in the Grid.
For example:
private async void myGrid_RightTapped(object sender, RightTappedRoutedEventArgs e)
{
var RightTapGrid = sender as Grid;
var childernElements = RightTapGrid.Children;
foreach (var item in childernElements)
{
var grid = item as Grid;
if (grid != null)
{
var itemchildernElements = grid.Children;
foreach (var text in itemchildernElements)
{
var textBlock = text as TextBlock;
var dialog = new ContentDialog()
{
Title = textBlock.Text,
MaxWidth = this.ActualWidth
};
dialog.PrimaryButtonText = "OK";
dialog.SecondaryButtonText = "Cancel";
await dialog.ShowAsync();
break;
}
}
}
}

If you get your Binding Data from Class called ClassName
You can try this code
XAML:
<ListView x:Name="chatUI" VerticalAlignment="Bottom" SelectionChanged="chatUI_SelectionChanged">
<ListView.ItemTemplate>
<DataTemplate>
<Grid x:Name="myGrid" Width="340" Background="{Binding Background}" HorizontalAlignment="{Binding GridHorizontalAlign}" Margin="10,0,10,10" MinHeight="45" BorderBrush="#FF003A4F" BorderThickness="0,0,0,2">
<Polygon Visibility="{Binding RightVisibility}" Fill="{Binding Background}" Points="0,0 5,6, 0,12" VerticalAlignment="Top" HorizontalAlignment="Right" Margin="0,0,-5,0" />
<Polygon Visibility="{Binding LeftVisibility}" Fill="{Binding Background}" Points="5,0 0,6, 5,12" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="-5,0,0,0" />
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Text="{Binding Text}" TextWrapping="Wrap" FontSize="15" FontFamily="Segoe UI" Foreground="White" Margin="10,10,10,0"/>
<TextBlock Grid.Row="1" Text="{Binding Time}" TextWrapping="Wrap" FontSize="11" FontFamily="Segoe UI" Foreground="LightGray" Margin="10,0,10,5" VerticalAlignment="Bottom" TextAlignment="Right"/>
</Grid>
</Grid>
</DataTemplate>
</Listview.ItemTemplate>
And add SelectionChanged Event :
private void chatUI_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListView view = (ListView)sender;
//Get Selected Item
ClassName class = view.SelectedItem as ClassName;
string path = class.Text;
// Now we have Text of selected item in Listview
}

Cant Find Control Windows Phone 8.1 UAP

I am trying to find a control under my xaml in the hub control of windows phone 8.1. It may be the case my method works fine on desktop as I have testest it in wpf before but I am porting it to windows phone and may not work the same.
<Grid>
<Hub Header="Lists" Name="mainHub" >
<HubSection MinWidth="600" Name="lattestLists" Header="New Lists">
<DataTemplate>
<Grid>
<ListBox Background="Transparent" Margin="6" Height="auto" BorderThickness="2" MaxHeight="580" Grid.Row="1" x:Name="listBoxobj" >
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Width="350" >
<Border Margin="5" BorderBrush="White" BorderThickness="1">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<TextBlock Margin="5,0,0,0" Grid.Row="0" x:Name="NameTxt" TextWrapping="Wrap" Text="{Binding Name}" FontSize="28" Foreground="White"/>
<TextBlock Grid.Row="0" Text=">" FontSize="28" HorizontalAlignment="Right" VerticalAlignment="Center" Foreground="White"/>
<TextBlock Margin="5,0,0,0" Grid.Row="1" x:Name="PhoneTxt" TextWrapping="Wrap" Foreground="White" FontSize="18" Text="{Binding PhoneNumber}" />
<TextBlock HorizontalAlignment="Right" Margin="0,0,35,0" Grid.Row="3" x:Name="CreateddateTxt" Foreground="White" FontSize="18" TextWrapping="Wrap" Text="{Binding CreationDate}" />
</Grid>
</Border>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</DataTemplate>
</HubSection>
<HubSection Header="Tech" IsHeaderInteractive="True"
Background="#222222" MinWidth="250">
<DataTemplate>
<StackPanel>
<TextBlock Text="Tech news goes here."
Style="{ThemeResource BodyTextBlockStyle}" />
<TextBlock Text="Click the header to go to the Tech page."
Style="{ThemeResource BodyTextBlockStyle}" />
</StackPanel>
</DataTemplate>
</HubSection>
<HubSection Header="Sports" IsHeaderInteractive="True"
Background="#444444" MinWidth="250">
<DataTemplate>
<StackPanel>
<TextBlock Text="Sports news goes here."
Style="{ThemeResource BodyTextBlockStyle}" />
<TextBlock Text="Click the header to go to the Sports page."
Style="{ThemeResource BodyTextBlockStyle}" />
</StackPanel>
</DataTemplate>
</HubSection>
</Hub>
</Grid>
I am trying to use the following method to find the lsitbox but its not working
ListBox listBoxobjc = FindChildControl<ListBox>(this, "listBoxobj") as ListBox;
listBoxobjc.ItemsSource = DB_ContactList.OrderByDescending(i => i.id).ToList();//Binding DB data to LISTBOX and Latest contact ID can Display first.
This is the method FindChildControl
private DependencyObject FindChildControl<T>(DependencyObject control, string ctrlName)
{
int childNumber = VisualTreeHelper.GetChildrenCount(control);
for (int i = 0; i < childNumber; i++)
{
DependencyObject child = VisualTreeHelper.GetChild(control, i);
FrameworkElement fe = child as FrameworkElement;
// Not a framework element or is null
if (fe == null) return null;
if (child is T && fe.Name == ctrlName)
{
// Found the control so return
return child;
}
else
{
// Not found it - search children
DependencyObject nextLevel = FindChildControl<T>(child, ctrlName);
if (nextLevel != null)
return nextLevel;
}
}
return null;
}
Edit
I debuged the code and its showing the control as null even though I have done the same way as i would

I have replace my method to find children a couple of times during the different versions of Windows Phone / Windows Runtime with this one being the most reliable. Just in case you're not able to spot the mistake you could also try this one and see if it yields better results:
public T FindElementByName<T>(DependencyObject element, string sChildName) where T : FrameworkElement
{
T childElement = null;
var nChildCount = VisualTreeHelper.GetChildrenCount(element);
for (int i = 0; i < nChildCount; i++)
{
FrameworkElement child = VisualTreeHelper.GetChild(element, i) as FrameworkElement;
if (child == null)
continue;
if (child is T && child.Name.Equals(sChildName))
{
childElement = (T)child;
break;
}
childElement = FindElementByName<T>(child, sChildName);
if (childElement != null)
break;
}
return childElement;
}
Also when using this method shortly after creating / loading content I call UpdateLayout beforehand:
this.UpdateLayout();
But be careful - this is not one of the performance-friendliest methods (see also: https://msdn.microsoft.com/en-us/library/windows/apps/windows.ui.xaml.uielement.updatelayout).

Windows Phone 8.1 Listview unique first and last item template

Last year I made an app for Windows Phone 8, containing a LongListSelector with a unique first and last item template, as described here:
LongListSelector different item template for first and last item
I recently updated the app to Windows Phone 8.1 Store and this functionality broke. Here's my class (the only difference from the post being, that I'm using a ListView instead of a LongListSelector for Windows Phone 8.1 Store, since LongListSelector is not a part of the Windows Phone 8.1 Store framework):
public abstract class TemplateSelector : ContentControl
{
public abstract DataTemplate SelectTemplate(object item, int index, int totalCount, DependencyObject container);
protected override void OnContentChanged(object oldContent, object newContent)
{
base.OnContentChanged(oldContent, newContent);
var parent = GetParentByType<ListView>(this);
var index = (parent.ItemsSource as IList).IndexOf(newContent);
var totalCount = (parent.ItemsSource as IList).Count;
ContentTemplate = SelectTemplate(newContent, index, totalCount, this);
}
private static T GetParentByType<T>(DependencyObject element) where T : FrameworkElement
{
T result = null;
DependencyObject parent = VisualTreeHelper.GetParent(element);
while (parent != null)
{
result = parent as T;
if (result != null)
{
return result;
}
parent = VisualTreeHelper.GetParent(parent);
}
return null;
}
}
The problem is that this:
DependencyObject parent = VisualTreeHelper.GetParent(element);
of the GetParentByType function returns null for some reason. Anyone knows why or have an alternative solution?
Below is my XAML code(with a few xmlns's removed). The DataTrigger is there because sometimes a unique first item template is enough (controlled by the LoadMore property of the ViewModel, which is a bool).
<controls:WP81Page
xmlns:core="using:Microsoft.Xaml.Interactions.Core"
xmlns:interactivity="using:Microsoft.Xaml.Interactivity"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<controls:WP81Page.Resources>
<DataTemplate x:Key="first">
<Grid HorizontalAlignment="Left" Width="Auto" Height="200">
<Border BorderThickness="1" BorderBrush="Black" Visibility="{Binding NoLargeImage, Converter={StaticResource BoolToVisibilityConverter}}" >
<Image Source="/Images/default-image.png" Stretch="UniformToFill" />
</Border>
<Border BorderThickness="1" BorderBrush="Black" Visibility="{Binding NoLargeImage, Converter={StaticResource BoolToVisibilityConverterReverse}}" >
<Image Source="{Binding LargeImageUrl}" Stretch="UniformToFill" />
</Border>
<StackPanel VerticalAlignment="Bottom" Background="#7F000000" >
<TextBlock Text="{Binding Header}" VerticalAlignment="Center" TextWrapping="Wrap" Foreground="White" FontWeight="Bold" Margin="15,0,15,15"/>
</StackPanel>
</Grid>
</DataTemplate>
<DataTemplate x:Key="default">
<StackPanel Orientation="Horizontal" Margin="0,10,0,0" Height="105" Width="Auto">
<Border BorderThickness="1" BorderBrush="Black" Margin="0,2" Visibility="{Binding NoSmallImage, Converter={StaticResource BoolToVisibilityConverter}}" >
<Image Source="/Images/default-image.png" Width="130" Height="100" Stretch="UniformToFill" />
</Border>
<Border BorderThickness="1" BorderBrush="Black" Margin="0,2" Visibility="{Binding NoSmallImage, Converter={StaticResource BoolToVisibilityConverterReverse}}">
<Image Source="{Binding SmallImageUrl}" Width="130" Height="100" Stretch="UniformToFill"/>
</Border>
<StackPanel Orientation="Vertical" Width="300" Margin="8,0,0,0">
<TextBlock Text="{Binding Header}" TextWrapping="Wrap" FontWeight="Bold" />
<TextBlock Margin="0,3,0,0" Text="{Binding DisplayDate}" TextWrapping="Wrap" Foreground="#FFB9B9B9" FontSize="16" />
</StackPanel>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="last">
<TextBlock Text="hent flere nyheder" FontSize="25" Margin="0,20" TextWrapping="Wrap" VerticalAlignment="Center" HorizontalAlignment="Center" Height="75" />
</DataTemplate>
<DataTemplate x:Key="UniqueFirstTemplateSelector">
<common:UniqueFirstTemplateSelector Content="{Binding}" First="{StaticResource first}" Default="{StaticResource default}" HorizontalAlignment="Stretch"/>
</DataTemplate>
<DataTemplate x:Key="UniqueFirstAndLastTemplateSelector">
<common:UniqueFirstAndLastTemplateSelector Content="{Binding}" First="{StaticResource first}" Default="{StaticResource default}" Last="{StaticResource last}" HorizontalAlignment="Stretch"/>
</DataTemplate>
</controls:WP81Page.Resources>
<controls:WP81Page.DataContext>
<viewModels:NewsViewModel/>
</controls:WP81Page.DataContext>
<Grid x:Name="LayoutRoot" Style="{Binding Source={StaticResource Background}}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ProgressBar Grid.Row="0" VerticalAlignment="Top" IsIndeterminate="True" Background="Transparent" Foreground="White" Visibility="{Binding IsLoading, Converter={StaticResource BoolToVisibilityConverter}}" />
<StackPanel Grid.Row="0" Margin="12,17,0,28">
<TextBlock Text="NYHEDER" FontSize="35" FontWeight="Bold" Style="{StaticResource PhoneTextNormalStyle}"/>
</StackPanel>
<Grid x:Name="ContentPanel" Grid.Row="1">
<controls:WP81ListView x:Name="listSelector" Margin="22,0" Grid.Row="2" ItemsSource="{Binding News}" Command="{Binding NewsEntrySelectedCommand}" >
<interactivity:Interaction.Behaviors>
<core:DataTriggerBehavior Binding="{Binding LoadMore}" Value="True">
<core:ChangePropertyAction TargetObject="{Binding ElementName=listSelector}"
Value="{StaticResource UniqueFirstAndLastTemplateSelector}"
PropertyName="ItemTemplate" />
</core:DataTriggerBehavior>
<core:DataTriggerBehavior Binding="{Binding LoadMore}" Value="False">
<core:ChangePropertyAction TargetObject="{Binding ElementName=listSelector}"
Value="{StaticResource UniqueFirstTemplateSelector}"
PropertyName="ItemTemplate" />
</core:DataTriggerBehavior>
</interactivity:Interaction.Behaviors>
</controls:WP81ListView>
</Grid>
</Grid>
</controls:WP81Page>
Thank you in advance.
EDIT
Alright, so what I want is not for the first and last item to be unique all the time. I'm making a news feed where the last item is only unique when there are more news entries to load (when the last item are clicked, more news entries are added to the ListView). If however, the end of the news entries are reached, the last item must not be unique (hence the combination with interactivity).

ListView has a property called ItemTemplateSelector which accepts objects based on DataTemplateSelector. So you need to change a couple of things to get it to work.
First of all, the definition of your template selector. It needs to be based on DataTemplateSelector and override method called SelectTemplateCore. It takes an object which is a ListViewItem. At that point you can go up the VisualTree to get the ListView and choose the DataTemplate based on index.
public class MyTemplateSelector : DataTemplateSelector
{
public DataTemplate First { get; set; }
public DataTemplate Default { get; set; }
public DataTemplate Last { get; set; }
protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
{
var listViewItem = container as ListViewItem;
var listView = GetParentByType<ListView>(listViewItem);
var index = (listView.ItemsSource as IList).IndexOf(item);
var totalCount = (listView.ItemsSource as IList).Count;
if (index == 0)
return First;
else if (index == totalCount - 1)
return Last;
else
return Default;
}
private T GetParentByType<T>(DependencyObject element) where T : FrameworkElement
{
T result = null;
DependencyObject parent = VisualTreeHelper.GetParent(element);
while (parent != null)
{
result = parent as T;
if (result != null)
{
return result;
}
parent = VisualTreeHelper.GetParent(parent);
}
return null;
}
}
Then, you need to create an instance of it in static resources
<local:MyTemplateSelector x:Key="SelectingTemplate"
First="{StaticResource first}"
Default="{StaticResource default}"
Last="{StaticResource last}" />
with the First, Default and Last DataTemplates, just like you did before.
The last step is to apply it to the ListView you're using.
<ListView ItemsSource="{Binding SomeItemsSource}"
ItemTemplateSelector="{StaticResource SelectingTemplate}" />
And that's it!