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Data Binding to a Property within a Collection in another Collection

I'm having an issue databinding to a property that is two levels deep in a collection.
The object is structured as such
Collection
--Data
--Name
--Collection
--Name
--Data
So essentially its a collection within a collection, and I can't seem to bind to the name within the contained collection.
I can bind to all the properties of the initial collection, including the collection within it, but as soon as I try to bind to the name property of the internal collection I get bad bindings.
XAML Portion
<TabControl ItemsSource="{Binding Path=BMOverlayCollection}" Grid.Column="0" Grid.Row="4" Grid.ColumnSpan="4">
<TabControl.ItemTemplate>
<!-- this is the header template-->
<DataTemplate>
<TextBlock
Text="{Binding Name}" />
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<!-- this is the body of the TabItem template-->
<DataTemplate>
<TextBlock
Text="{Binding Graphics.Name}" />
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
C# Portion
public class BMGraphicsOverlayCollection : INotifyPropertyChanged, IEnumerable
{
#region Event Property
public event PropertyChangedEventHandler? PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
private ObservableCollection<NamedOverlay> _namedOverlays;
public ObservableCollection<NamedOverlay> NamedOverlays { get { return _namedOverlays; } set { _namedOverlays = value; OnPropertyChanged(); } }
public BMGraphicsOverlayCollection()
{
_namedOverlays = new ObservableCollection<NamedOverlay>();
}
public void Add(string name, GraphicsOverlay overlay)
{
NamedOverlay mOverlay = new NamedOverlay();
mOverlay.Name = name;
mOverlay.Overlay = overlay;
_namedOverlays.Add(mOverlay);
}
public void Add(string name, GraphicsOverlay overlay, IList<MapGraphic> graphics)
{
NamedOverlay mOverlay = new NamedOverlay();
mOverlay.Name = name;
mOverlay.Overlay = overlay;
mOverlay.Graphics = new ObservableCollection<MapGraphic>(graphics);
_namedOverlays.Add(mOverlay);
}
public IEnumerator GetEnumerator()
{
return _namedOverlays.GetEnumerator();
}
}
public class NamedOverlay : INotifyPropertyChanged
{
#region Event Property
public event PropertyChangedEventHandler? PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
private string _name;
public string Name { get { return _name; } set { _name = value; OnPropertyChanged(); } }
private GraphicsOverlay _overlay;
public GraphicsOverlay Overlay { get { return _overlay; } set { _overlay = value; OnPropertyChanged(); } }
private ObservableCollection<MapGraphic> _graphics;
public ObservableCollection<MapGraphic> Graphics { get { return _graphics; } set { _graphics = value; OnPropertyChanged(); } }
}
}
And the MapGraphic pertinent part
private string _name;
public string Name
{
get
{
if (_name == null)
{
return "Unnamed";
} else
{
return _name;
}
}
set
{
_name = value; OnPropertyChanged();
}
}
Thanks in advance for the help.

According to your code, Your data structure was NamedOverlays[].Graphics[].Name, but your binding path was NamedOverlays[].Graphics.Name. That's the reason of the bad binding. Change
<TextBlock Text="{Binding Graphics.Name}" />
to (if you want to show all names in Graphics)
<ListBox ItemsSource="{Binding Graphics}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
or (if you just want to show 1st name in graphics)
<TextBlock Text="{Binding Graphics[0].Name}" />
will fix the problem.

ObservableCollection binding to listbox ui doesn't update

I know I should use the MVVM pattern but I'm trying to get step by step closer to it. So here is my Listbox:
<ListBox x:Name="BoardList" ItemsSource="{Binding notes}" >
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
<TextBox IsReadOnly="True" ScrollViewer.VerticalScrollBarVisibility="Visible" Text="{Binding text}" TextWrapping="Wrap" Foreground="DarkBlue"></TextBox>
<AppBarButton Visibility="{Binding visibility}" Icon="Globe" Click="OpenInBrowser" x:Name="Link"></AppBarButton>
<AppBarButton Icon="Copy" Click="Copy"></AppBarButton>
<AppBarButton Icon="Delete" Click="Delete"></AppBarButton>
</StackPanel>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
In the Mainpage.xaml.cs I declare the following:
ObservableCollection<BoardNote> notes = new ObservableCollection<BoardNote>();
So if I understood this right I don't need to care about the "INotifyCollectionChanged" stuff because I'm using an observablecollection?
So I got for example a textbox like this:
<Textbox x:Name="UserInputNote" Placeholdertext="Type in a text for your note"></Textbox>
And a button to Add the new note to the ObservableCollection and the click event is just like this:
notes.Add(new BoardNote(UserInputNote.Text));
So now the UI should update every time the user clicks the button to save a new note. But nothing happens. What did I do wrong?
If you need it here is the BoardNote class:
class BoardNote
{
public string text
{
get; set;
}
public BoardNote(string text)
{
this.text = text;
}
public Visibility visibility
{
get
{
if (text.StartsWith("http"))
return Visibility.Visible;
else
return Visibility.Collapsed;
}
}
}

You need to implement INotifyPropertyChanged. Here's one way of doing it.
Create this NotificationObject class.
public class NotificationObject : INotifyPropertyChanged
{
protected void RaisePropertyChanged<T>(Expression<Func<T>> action)
{
var propertyName = GetPropertyName(action);
RaisePropertyChanged(propertyName);
}
private static string GetPropertyName<T>(Expression<Func<T>> action)
{
var expression = (MemberExpression)action.Body;
var propertyName = expression.Member.Name;
return propertyName;
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
public event PropertyChangedEventHandler PropertyChanged;
}
Then your BoardNote class will inherit it this way:
class BoardNote : NotificationObject
{
private string _text
public string Text
{
get {return _text;}
set
{
if(_text == value) return;
_text = value;
RaisePropertyChanged(() => Text);
}
}
public BoardNote(string text)
{
this.text = text;
}
public Visibility visibility
{
get
{
if (text.StartsWith("http"))
return Visibility.Visible;
else
return Visibility.Collapsed;
}
}
}

MVVM WPF ListBox Entry not updating

I recently started to learn the MVVM Pattern and created a simple application to test a few things.
I have a simple View with:
ListBox holding ObservableCollection of Items
Delete Button
New Button
TextBox for Item Description
TextBox for Item Value
Everything works except for the fact that, if i'm updating the item description the ListBox entry isn't updating. I read some articles about this, so i think it has something to do with CollectionChanged isn't called. I tried some possible solutions to this problem, but none of them worked. So maybe there is something generally wrong with my approach.
Hopefully someone can help me with this problem.
Model/Item.cs
internal class Item : INotifyPropertyChanged
{
#region Fields
private string value;
private string description;
#endregion
#region Constructors
public Item()
{
}
public Item(string value, string description) {
this.description = description;
this.value = value;
}
#endregion
public String Value
{
get
{
return value;
}
set
{
this.value = value;
OnPropertyChanged("Value");
}
}
public String Description
{
get
{
return description;
}
set
{
description = value;
OnPropertyChanged("Description");
}
}
#region Overrides
public override string ToString()
{
return description;
}
#endregion String Override
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
}
ViewModel/MainViewModel.cs
...
private ObservableCollection<Item> items;
private Item selectedItem;
public ObservableCollection<Item> Items {
get
{
return items;
}
set
{
items = value;
OnPropertyChanged("Items");
}
}
public Item SelectedItem {
get
{
return selectedItem;
}
set
{
selectedItem = value;
OnPropertyChanged("SelectedItem");
}
}
...
View/MainWindow.xaml
...
<Button Content="New" Command="{Binding NewCommand}" />
<Button Content="Delete" Command="{Binding DeleteCommand}" />
<ListBox x:Name="lbxItems" ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem}" />
<TextBox Text="{Binding SelectedItem.Description}" />
<TextBox Text="{Binding SelectedItem.Value}" />
...

with this ItemTemplate it should work
<ListBox Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="2" ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=Value}" Margin="0,0,10,0/>
<TextBlock Text="{Binding Path=Description}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

How you generate a PropertyChangedEvent in your model class?
try this:
internal class Range : INotifyPropertyChanged
{
private string _value;
public string Value
{
get { return _value; }
set
{
if (_value == value) return;
_value = value;
OnPropertyChanged("Value");
}
}
//Do same for the Description property
//Do not forgot implement INotifyPropertyChanged interface here
}
I hope this help you
Oh! After your update it is clearly. You does not use any datatemplate for listbox item, so WPF calls the ToString() method for show item without DT. But when you update any property, WPF does not know about this because object does not changing.
Use Datatemplate or try call OnPropertyChanged with empty string.

EditableTextBlock - TreeView - Virtualization

for the past couple of weeks I've been trying to get the EditableTextBlock (from codeproject) working on my TreeView.
The control has a property IsInEditMode which when set to true changes it to a TextBox.
The TreeView is virtualized and declared as follows:
<TreeView x:Name="treeEnvironment"
Margin="0,29,0,0" BorderThickness="0"
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Recycling">
</TreeView>
The TreeView uses the ItemsSource property to get it's data and the value of this is always a single instance of a class (lets call it A). This class contains a list of instances of another type (lets call it B). And this last class contains a list of instances of yet another class (lets call it `C). This is how it looks like in the code:
class A
{
public String Name;
public ObservableCollection<B> Items;
}
class B
{
public String Name;
public ObservableCollection<C> Items;
}
class C
{
public String Name;
public bool IsRenaming;
}
For each of these three classes there is an HierarchicalDataTemplate defined in MainWindow.Resources as follows:
<DataTemplate DataType="{x:Type C}">
<StackPanel Orientation="Horizontal">
<StackPanel.ContextMenu>
<ContextMenu>
<MenuItem Header="Rename" Click="C_Rename_Click" />
</ContextMenu>
</StackPanel.ContextMenu>
<v:EditableTextBlock Text="{Binding Path=Name}" IsInEditMode="{Binding Path=IsRenaming, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel>
</DataTemplate>
<HierarchicalDataTemplate DataType="{x:Type B}" ItemsSource="{Binding Path=Items, Mode=OneWay}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=Name}" ToolTip="{Binding Path=Name}" />
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type A}" ItemsSource="{Binding Path=Items, Mode=OneWay}">
<StackPanel Orientation="Horizontal">
<Image Source="icons/icon_A.png" Width="16" Height="16" />
<TextBlock Text="{Binding Path=Name}" ToolTip="{Binding Path=Name}" />
</StackPanel>
</HierarchicalDataTemplate>
None of the DataTemplate have keys so that it is applied automatically.
The event that is triggered when the rename MenuItem of C's context menu is clicked, is defined as follows:
private void C_Rename_Click(object sender, RoutedEventArgs e)
{
C instance = (sender as FrameworkElement).DataContext as C;
if (instance != null) {
instance.IsRenaming = true;
} else {
MessageBox.Show("DEBUG: C_Rename_Click(" + sender.ToString() + ", " + e.ToString() + ") : instance == null");
}
}
The problem is that the EditableTextBlock does not turn into a TextBox when the IsRenaming property is set to true on the instance of C that was chosen to be renamed.
The EditableTextBlock works just fine when I place it as a normal control.
My guess is that it has to do with virtualization. Any help would be appreciated.
Thank you for your time, best regards,
100GPing100.

class A, B, C need to implement INotifyPropertyChanged for any changes made to them to be propagated to the UI. You can either implement it in each class individually or have a base class implement INPC and derive your classes from this base class.
Something like:
public class MyBaseViewModel : INotifyPropertyChanged {
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName) {
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class A : MyBaseViewModel {
private string _name;
public string Name {
get {
return _name;
}
set {
_name = value;
OnPropertyChanged("Name");
}
}
private ObservableCollection<B> _items;
public ObservableCollection<B> Items {
get {
return _items;
}
set {
_items = value;
OnPropertyChanged("Items");
}
}
}
public class B : MyBaseViewModel {
private string _name;
public string Name {
get {
return _name;
}
set {
_name = value;
OnPropertyChanged("Name");
}
}
private ObservableCollection<C> _items;
public ObservableCollection<C> Items {
get {
return _items;
}
set {
_items = value;
OnPropertyChanged("Items");
}
}
}
public class C : MyBaseViewModel {
private string _name;
public string Name {
get {
return _name;
}
set {
_name = value;
OnPropertyChanged("Name");
}
}
private bool _isRenaming;
public bool IsRenaming {
get {
return _isRenaming;
}
set {
_isRenaming = value;
OnPropertyChanged("IsRenaming");
}
}
}
Now when you change IsRenaming in your code, you will see the update propagate to the UI and the TextBlock switch to a TextBox.
Side-note
Please have a look at MVVM. If you're not sure about it. Get to learn it slowly cos it helps UI development in WPF quite a bit.

How to bind the view model to the view

I am having trouble binding my View Model to my View. I am a beginner with MVVM, but I believe I am implementing my system (almost) correctly. I have a Model that contains data, which I am getting in my View Model, and then when my page is navigated to, I am attempting to grab that View Model data and binding it to the View.
My issue is that I have a ListBox in my View with 3 objects per item, and I cannot seem to bind to it correctly for each item in my list.
MainPage.xaml
<ListBox x:Name="FavoritesListBox" ItemsSource="{Binding FavoriteItems}"
SelectionChanged="FavoritesListBox_SelectionChanged">
<StackPanel Orientation="Horizontal" Margin="12,0,12,0">
<Image x:Name="favicon" Source="{Binding Favicon}"
Width="50" Height="50"/>
<StackPanel>
<TextBlock x:Name="favoritesName" Text="{Binding Name}"
FontSize="{StaticResource PhoneFontSizeExtraLarge}"/>
<TextBlock x:Name="favoritesAddress"
Text="{Binding Address}" Margin="12,0,0,0"/>
</StackPanel>
</StackPanel>
</ListBox>
MainPage.xaml.cs
public FavoritesPage()
{
InitializeComponent();
// Set the data context of the listbox control to the sample data
FavoritesListBox.DataContext = App.ViewModel;
}
App.xaml.cs
private static MainViewModel viewModel = null;
public static MainViewModel ViewModel
{
get
{
// Delay creation of the view model until necessary
if (viewModel == null)
viewModel = new MainViewModel();
return viewModel;
}
}
MainViewModel.cs
public ObservableCollection<ItemViewModel> FavoriteItems { get; private set; }
public MainViewModel()
{
//FavoriteItems = new ObservableCollection<ItemViewModel>();
FavoriteItems = Settings.FavoritesList.Value;
}
Settings.cs (The Model)
public static Setting<ObservableCollection<ItemViewModel>> FavoritesList =
new Setting<ObservableCollection<ItemViewModel>>(
"Favorites",
new ObservableCollection<ItemViewModel>());
ItemViewModel.cs
private string _favicon;
public string Favicon
{
get
{
return _favicon;
}
set
{
if (value != _favicon)
{
_favicon = value;
NotifyPropertyChanged("Favicon");
}
}
}
private string _name;
public string Name
{
get
{
return _name;
}
set
{
if (value != _name)
{
_name = value;
NotifyPropertyChanged("Name");
}
}
}
private string _address;
public string Address
{
get
{
return _address;
}
set
{
if (value != _address)
{
_address = value;
NotifyPropertyChanged("Address");
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (null != handler)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
..and this is where and how I am saving each item (which should have three properties listed in the ItemViewModel
void addToFavorites_Click(object sender, EventArgs e)
{
var favoriteItem =
new ItemViewModel{
Favicon = "",
Name = "",
Address = TheBrowser.currentUrl() };
Settings.FavoritesList.Value.Add(favoriteItem);
}
Where FavoritesList is populated using an ItemViewModel containing 3 objects. The list is being populated correctly because during debugging I can see the entities in FavoritesList, but I am having an issue calling these entities in the view model to show up in my ListBox in the view?
I believe I am binding incorrectly but I'm not sure how to fix this?

In your XAML you bind to paths Name and Address do you have these 2 properties defined in your ItemViewModel?
Update after reading your code properly:
You are not updating the datatemplate of the Items of the Listbox. This is what you need to do:
<ListBox x:Name="FavoritesListBox" ItemsSource="{Binding FavoriteItems}" SelectionChanged="FavoritesListBox_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Margin="12,0,12,0">
<Image x:Name="favicon" Source="{Binding Favicon}" Width="50" Height="50"/>
<StackPanel>
<TextBlock x:Name="favoritesName" Text="{Binding Name}" FontSize="{StaticResource PhoneFontSizeExtraLarge}"/>
<TextBlock x:Name="favoritesAddress" Text="{Binding Address}" Margin="12,0,0,0"/>
</StackPanel>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

In addition to setting your DataContext to your viewmodel, (as mentioned in the comment linking to Creating ContextBinding XAML) , you also need to have your view model implement INotifyPropertyChanged (including ItemViewModel, which you don't show in your question)