How to collapse/hide ListBoxItem

Question

I've been adding search/filter functionalities in Edit Views and in two sub views, Transaction and Lease, I'd have to add some additional string properties in the Model if I want to add that functionality in the same way I did in other sub views like Plot, Space and Tenant:

in the ListBox of Lease view, I've Egypt: A/ Egypt: B and these have been converted with some IValueConverter this way in the DataTemplate:

space.SetBinding(Run.TextProperty, new Binding(nameof(Lease.SpaceId)) { Converter = App.convert.spaceId2spaceName });  
tenant.SetBinding(Run.TextProperty, new Binding(nameof(Lease.TenantId)) { Converter = App.convert.tenantId2TenantName });  

and similarly in the Transaction view, those values like BD: A | Receivable => Rent ... have been converted in this way:

...  
var tenant = new FrameworkElementFactory(typeof(Run)) { Name = "tenant" };  
...  
space.SetBinding(Run.TextProperty, new Binding(nameof(Transaction.SpaceId)) { Converter = App.convert.spaceId2spaceName });  
tenant.SetBinding(Run.TextProperty, new Binding(nameof(Transaction.TenantId)) { Converter = App.convert.tenantId2TenantName });  
control.SetBinding(Run.TextProperty, new Binding(nameof(Transaction.ControlId)) { Converter = App.convert.controlId2ControlName });  
head.SetBinding(Run.TextProperty, new Binding(nameof(Transaction.HeadId)) { Converter = App.convert.headId2headName });  
isCash.SetBinding(BiState.IsTrueProperty, new Binding(nameof(Transaction.IsCash)));  
amount.SetBinding(TextBlock.TextProperty, new Binding(nameof(Transaction.Amount)) { StringFormat = "N0" });  

so these two views don't have string properties I could add filter on. Instead of changing Lease and Transaction models, I wanted to search the content of the ListBoxItem and hide/show based on the query string of the searchbox. I've this event and handler in the Transaction view:

search.TextChanged += onQueryChanged;  
void onQueryChanged(string query) {  
    Debug.WriteLine(query);  
    foreach (Transaction item in transactions.Items) {  
        var listItem = (ListBoxItem)transactions.ItemContainerGenerator.ContainerFromItem(item);  
        var grid = listItem.ContentTemplate;  
        //grid.FindName("tenant", grid.VisualTree);  
        //listItem.Visibility = Visibility.Collapsed;  
    }  
}  

now, how to get the tenant string from the ContentTemplate and collapse ListBoxItem?

Answer 1

I made a sample to filter objects in ListBox, the groups hide when filter condition doesn't exist. It may give you some help.
XAML code:

 <Window.DataContext>  
        <local:ViewModel></local:ViewModel>  
    </Window.DataContext>  
    <Grid>  
        <Grid.RowDefinitions>  
            <RowDefinition Height="30"></RowDefinition>  
            <RowDefinition></RowDefinition>  
        </Grid.RowDefinitions>  
        <StackPanel Orientation="Horizontal" Margin="2">  
            <Label>Name：</Label>  
            <TextBox Width="100" Text="{Binding NameFilterStr,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>  
        </StackPanel>  
        <ListBox Name="lbMain"  Grid.Row="1" ItemsSource="{Binding StudentListView}">  
            <ListBox.ItemTemplate>  
                <DataTemplate>  
                    <StackPanel Orientation="Horizontal">  
                        <TextBlock Text="{Binding Name}"  
                            Width="150" />  
                        <TextBlock Text="{Binding Age}"  
                            Width="100" />  
                        <TextBlock Text="{Binding Description}"  
                            Width="100" />  
                    </StackPanel>  
                </DataTemplate>  
            </ListBox.ItemTemplate>  
            <ListBox.GroupStyle>  
                <GroupStyle>  
                    <GroupStyle.ContainerStyle>  
                        <Style TargetType="{x:Type GroupItem}">  
                            <Setter Property="Template">  
                                <Setter.Value>  
                                    <ControlTemplate TargetType="{x:Type GroupItem}">  
                                        <Expander IsExpanded="True" ExpandDirection="Down">  
                                            <Expander.Header>  
                                                <StackPanel Orientation="Horizontal">  
                                                    <TextBlock Text="Age:"></TextBlock>  
                                                    <TextBlock Text="{Binding Path=Name}" VerticalAlignment="Center" />  
                                                    <TextBlock Text="{Binding Path=ItemCount, StringFormat=Count:{0}}"  
                                                        VerticalAlignment="Center"  
                                                        Margin="5,0,0,0" />  
                                                </StackPanel>  
                                            </Expander.Header>  
                                            <ItemsPresenter />  
                                        </Expander>  
                                    </ControlTemplate>  
                                </Setter.Value>  
                            </Setter>  
                        </Style>  
                    </GroupStyle.ContainerStyle>  
                </GroupStyle>  
            </ListBox.GroupStyle>  
        </ListBox>  
    </Grid>  

C# code is:

public class ViewModel : INotifyPropertyChanged  
    {  
        public event PropertyChangedEventHandler PropertyChanged;  
  
        private List<Student> students = new List<Student>();  
        public List<Student> Students  
        {  
            get { return students; }  
            set { students = value; }  
        }  
  
        private string nameFilterStr;  
  
        public string NameFilterStr  
        {  
            get { return nameFilterStr; }  
            set  
            {  
                nameFilterStr = value;  
                this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("NameFilterStr"));  
                StudentListView.Refresh();  
            }  
        }  
  
        public ListCollectionView StudentListView { get; set; }  
        public ViewModel()  
        {  
            StudentListView = new ListCollectionView(Students);  
            Students.Add(new Student() { Name = "AA1", Age = 12, Description = "654646" });  
            Students.Add(new Student() { Name = "AA2", Age = 12, Description = "7967969" });  
            Students.Add(new Student() { Name = "AA3", Age = 13, Description = "11111123" });  
            Students.Add(new Student() { Name = "BB1", Age = 14, Description = "123131" });  
            Students.Add(new Student() { Name = "BB6", Age = 13, Description = "232525" });  
            Students.Add(new Student() { Name = "BB7", Age = 16, Description = "57474674" });  
  
            StudentListView.GroupDescriptions.Add(new PropertyGroupDescription("Age"));  
            StudentListView.Filter = Filter;  
        }  
        private bool Filter(object obj)  
        {  
            Student s = obj as Student;  
            if (s == null) return false;  
  
            if (string.IsNullOrEmpty(NameFilterStr))  
            {  
                return true;  
            }  
            else if (!string.IsNullOrEmpty(NameFilterStr))  
            {  
                if (s.Name.Contains(NameFilterStr))  
                {  
                    return true;  
                }  
                return false;  
            }            
            else  
            {  
                if (s.Name.Contains(NameFilterStr) )  
                {  
                    return true;  
                }  
                return false;  
            }  
        }  
    }  
  
    public class Student  
    {  
        public string Name { get; set; }  
        public int Age { get; set; }  
        public string Description { get; set; }  
    }  

The Result picture is:

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

FindVisualChild works, so with this:

void onQueryChanged(string query) {  
    foreach (Transaction item in transactions.Items) {  
        var listItem = (ListBoxItem)transactions.ItemContainerGenerator.ContainerFromItem(item);  
        if (string.IsNullOrWhiteSpace(query))   
            listItem.Visibility = Visibility.Visible;  
              
        else {  
            var presenter = FindVisualChild<ContentPresenter>(listItem);  
            var grid = listItem.ContentTemplate;  
            var tenant = (Run)grid.FindName("tenant", presenter);  
            if (!tenant.Text.ToLower().Contains(query.Trim().ToLower())) {  
                listItem.Visibility = Visibility.Collapsed;  
            }  
        }  
    }  
}  

it works perfectly for A but for B there's a problem:

B doesn't exist in Africa and North America BUT those group names are still visible! I've tried with HidesIfEmpty = true in GroupStyle of the ListBox:

transactions = new ListBox() {  
    BorderThickness = new Thickness(0, 0, 1, 0),  
    HorizontalContentAlignment = HorizontalAlignment.Stretch,  
    ItemTemplate = new TransactionTemplate(),  
    GroupStyle = {  
        new GroupStyle() {  
            HidesIfEmpty = true,  
            ContainerStyle = new Style(typeof(GroupItem)){  
                Setters = {  
                    new Setter(GroupItem.TemplateProperty, new GroupedTransactionTemplate())  
                }  
            }  
        }  
    }  
};  

BUT that doesn't work! How to hide those Groups where B doesn't exist?