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Listbox focus reset after selecting any item

I have a listbox in my WPF project filled by a MYSql database. When I scroll anywhere in the listbox and select an item, it immediately jumps to the first item and show the list from the beginning. I tried this solution but it gives me NullException. Here is the code:
private void listBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var addedItems = e.AddedItems;
var selectedItem = (object)null;
if (addedItems.Count > 0)
{
selectedItem = addedItems[0];
}
object id = (((System.Data.DataRowView)selectedItem).Row.ItemArray[0]);
object name = (((System.Data.DataRowView)selectedItem).Row.ItemArray[1]);
object selectedType = (((System.Data.DataRowView)selectedItem).Row.ItemArray[2]);
}
and xaml part:
<ScrollViewer Width="582.5" Name="scrollViewer" HorizontalAlignment="Center" Background="Transparent" VerticalAlignment="Bottom" VerticalScrollBarVisibility="Disabled" HorizontalScrollBarVisibility="Hidden" >
<ListBox x:Name="listBox" SelectionMode="Single" Visibility="Hidden" IsEnabled="False" ScrollViewer.VerticalScrollBarVisibility="Disabled" ScrollViewer.HorizontalScrollBarVisibility="Disabled" HorizontalAlignment="Center" Background="Transparent" BorderBrush="Transparent" SelectionChanged="listBox_SelectionChanged" ItemsSource="{Binding Source={StaticResource TypeTable}}" HorizontalContentAlignment="Center" RenderTransformOrigin="0.5,0.5" Padding="0,0,0,90" >
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Name="stackPanel2" CanHorizontallyScroll="True" Orientation="Horizontal" HorizontalAlignment="Right" Height="180" Width="180" >
<Image Margin="3" Source="{Binding pic_path}" RenderOptions.BitmapScalingMode="Fant" RenderOptions.EdgeMode="Aliased"/>
<TextBox Margin="3" Text="{Binding name}" Visibility="Visible"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</ScrollViewer>

Deleting items from list in uwp

I am trying to delete items from my list on click of delete button but clicking once the list only gets refreshed and clicking again deletes item from the list.
Here is my code:
private void AppBarButton_Click(object sender, RoutedEventArgs e)
{
var query = BreakfastList.SelectedItems;
foreach (var item in query)
{
conn.Delete(item);
}
if (Item1.IsSelected)
{
List<DbManager> people = (from p in conn.Table<DbManager>()
select p).OrderByDescending(q => q.id).ToList();
BreakfastList.ItemsSource = people;
}
else if (Item2.IsSelected)
{
List<DbManager> people = conn.Table<DbManager>().OrderByDescending(q => q.id).Where(q => q.Reading == "Breakfast").ToList();
BreakfastList.ItemsSource = people;
}
else if (Item3.IsSelected)
{
List<DbManager> people = conn.Table<DbManager>().OrderByDescending(q => q.id).Where(q => q.Reading == "Lunch").ToList();
BreakfastList.ItemsSource = people;
}
else if (Item4.IsSelected)
{
List<DbManager> people = conn.Table<DbManager>().OrderByDescending(q => q.id).Where(q => q.Reading == "Dinner").ToList();
BreakfastList.ItemsSource = people;
}
}
Item1,2,3,4 are items in my combobox
My XAML for the list is:
<ListView
ScrollViewer.HorizontalScrollMode="Auto"
ScrollViewer.VerticalScrollMode="Enabled"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
Margin="0,0,0,0"
Name="BreakfastList"
Visibility="Visible"
>
<ListView.ItemTemplate>
<DataTemplate x:DataType="data:DbManager" >
<StackPanel Orientation="Horizontal" Width="Auto"
HorizontalAlignment="Left" VerticalAlignment="Center"
Height="Auto">
<StackPanel Width="50" Height="Auto" Name="GluStack" RelativePanel.AlignLeftWithPanel="True" >
<TextBlock Text="{Binding Glucose}" Margin="0,0,10,0" IsTextScaleFactorEnabled="False" />
</StackPanel>
<StackPanel Width="80" Height="Auto" Name="ReadStack" RelativePanel.RightOf="GluStack">
<TextBlock Text="{Binding Reading}" Margin="0,0,10,0" IsTextScaleFactorEnabled="False"/>
</StackPanel>
<StackPanel Width="130" Name="Read1Stack" Height="Auto" RelativePanel.RightOf="ReadStack">
<TextBlock Text="{Binding Reading1}" Margin="0,0,10,0" IsTextScaleFactorEnabled="False" />
</StackPanel>
<StackPanel Width="Auto" Name="DateStack" RelativePanel.RightOf="Read1Stack"
Height="Auto">
<TextBlock Text="{Binding Date}" IsTextScaleFactorEnabled="False" />
</StackPanel>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

Well, I'm not sure as this is not enough information, but based on your description the first time your method runs (first click), BreakfastList.SelectedItems is empty; therefore nothing gets deleted. Then you update the list by setting the ItemsSource on it. After setting the ItemsSource, BreakfastList.SelectedItems will be populated and that's why it works the second time.
If you set a breakpoint on:
var query = BreakfastList.SelectedItems;
Could you check if SelectedItems contains elements? Or in the next line if query has any?
Also, can you please give the xaml for BreakfastList? How is it initialized the first time?
(Sorry I'm writing this as an answer, but I don't have enough points to be able to write a comment on your question.)

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!

Combo box add item from template

Im trying to add items to the combo box from the code behind to the item template but im getting null. This is what I have so far:
XAML:
<ListBox x:Name="lsbCiertoYFalsoInsideTemplate" Margin="40,0,0,0" ItemTemplate="{StaticResource CiertoYFalsoExcerciseDataTemplate}"/>
App.xaml:
<DataTemplate x:Key="CiertoYFalsoExcerciseDataTemplate">
<Grid>
<StackPanel x:Name="stckCiertoYFalsoInsideTemplate" Margin="0" Orientation="Vertical" Width="1100">
<StackPanel x:Name="stckPreguntasCiertoYFalso" Orientation="Horizontal">
<Grid Height="50" Width="65" DataContext="{Binding CustomValueList}" VerticalAlignment="Top">
<ComboBox x:Name="cbExercises" Style="{StaticResource SA_ComboBoxStyle}" ItemsSource="{Binding CustomOption}" BorderBrush="#CC8C8C8C" VerticalAlignment="Top">
</ComboBox>
</Grid>
<TextBlock HorizontalAlignment="Center" Margin="5,3,0,0" TextWrapping="Wrap" Text="{Binding QuestionNumber}" VerticalAlignment="Top" FontWeight="Bold" Foreground="Black" Width="26" FontFamily="{Binding FontFamily, Source={StaticResource TextBlockStyleManager}}" FontSize="{Binding FontSize, Source={StaticResource TextBlockStyleManager}}"/>
<TextBlock TextWrapping="Wrap" Text="{Binding Question}" Foreground="Black" VerticalAlignment="Top" FontSize="{Binding FontSize, Source={StaticResource TextBlockStyleManager}}" Margin="10,3,0,0" Width="968" FontFamily="{Binding FontFamily, Source={StaticResource TextBlockStyleManager}}"/>
</StackPanel>
</StackPanel>
</Grid>
</DataTemplate>
The error im getting is object out of range.
Code:
private void ComboBoxExercises()
{
ComboBox comboBox = new ComboBox();
ComboboxItem item = new ComboboxItem();
item.Text = "A";
comboBox = (ComboBox)lsbCiertoYFalsoInsideTemplate.FindName("cbExercises");
comboBox.SelectedIndex = 0;
comboBox.Items.Add(item);
}
public class ComboboxItem
{
public string Text { get; set; }
public override string ToString()
{
return Text;
}
}

There's a disconnect in what you're trying to do here. You've specified an ItemTemplate - which defines how each item in the list will look.
But then you're trying to get one single ComboBox back out via the FindName function. Which leads me to believe that you're really intending to set the Template, not the ItemTemplate.
That said, I think the error you're getting is because you're setting the SelectedIndex to 0 when the ComboBox has no items in it. You're telling it to select the first one, but there's nothing to select. You should add the item first, then select it.

Make filter on wpf Listbox with Item template

I have a listbox in WPF databinded to a observablecollection
<ListBox Margin="0,0,-12,0" ItemsSource="{Binding ShopList}"
ScrollViewer.VerticalScrollBarVisibility="Auto"
Grid.Row="1"
Grid.ColumnSpan="2" KeyDown="ListBox_KeyDown" KeyUp="ListBox_KeyUp"
>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Margin="0,0,0,17" >
<!--Replace rectangle with image-->
<Rectangle Height="50" Width="50" Stroke="Black" StrokeThickness="6" Margin="12,0,9,0"/>
<StackPanel Width="Auto">
<TextBlock Text="{Binding Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
<TextBlock Text="{Binding Quantity}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}"/>
</StackPanel>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I then have a filter method I want called
private void ShopItemDay_Filter(object sender, FilterEventArgs e)
{
var item = e.Item as ShopItem;
e.Accepted = item.Day == 1;
}
But I cant find any properties on the Listbox to use a filter method like done here http://www.galasoft.ch/mydotnet/articles/article-2007081301.aspx

You need to create a 'view' on your collection. See the documentation for CollectionView.Filter. The framework will create a default view for all bound collections. You can add a filter as follows:
ICollectionView _customerView = CollectionViewSource.GetDefaultView(customers);
_customerView.Filter = CustomerFilter
private bool CustomerFilter(object item)
{
Customer customer = item as Customer;
return customer.Name.Contains( _filterString );
}
(From this tutorial);

As you can see in the article you linked to, the filter is not a property of the Control. It is a property of the CollectionViewSource which is a kind of wrapper around the collection. This wrapper allows for sorting, grouping and filtering.