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Databinding to an Object property fails, to the parent it is working

I tried to bind a property to a nested object, but it fails.
I have taken a look at those questions, but i think i made another mistake somewhere else. Maybe someone can give i hind.
WPF: How to bind to a nested property?
binding to a property of an object
To upper slider/textbox has a correct binding while the lower one fails to do so.
I have two sliders with corrosponding textboxes:
<StackPanel>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<TextBox Text="{Binding Path= boundnumber, Mode=TwoWay, FallbackValue='binding failed'}" ></TextBox>
<Slider Value="{Binding Path= boundnumber, Mode=TwoWay}" Width="500" Maximum="1000" ></Slider>
</StackPanel>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" DataContext="{Binding Path=myDatarow}">
<TextBox Text="{Binding Path= boundnumber, Mode=TwoWay, FallbackValue='binding failed'}" ></TextBox>
<Slider Value="{Binding Path= boundnumber, Mode=TwoWay}" Width="500" Maximum="1000" ></Slider>
</StackPanel>
</StackPanel>
Code behind:
public partial class MainWindow : INotifyPropertyChanged
{
public MainWindow()
{
DataContext = this;
InitializeComponent();
}
private int _boundnumber;
public int boundnumber
{
get { return _boundnumber; }
set
{
if (value != _boundnumber)
{
_boundnumber = value;
OnPropertyChanged();
}
}
}
Datarow myDatarow = new Datarow(11);
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyname = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
}
}
class Datarow : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyname = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
}
public Datarow()
{
}
public Datarow(int number)
{
boundnumber = number;
}
private int _boundnumber;
public int boundnumber
{
get { return _boundnumber; }
set
{
if (value != _boundnumber)
{
_boundnumber = value;
OnPropertyChanged();
}
}
}
}

You need to expose your myDatarow into a public property like your boundnumber.
private DataRow _myDatarow = new DataRow(11);
public DataRow myDataRow
{
get { return _myDatarow; }
}
And just an additional advice.
It's better to separate your DataContext class from the MainWindow.

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.

Databinding to a ListView inside a HubSection

I'm getting search results from the Bing API and adding each article to List and trying to bind it to a ListView in XAML but no results appear in the HubSection.
private List<NewsArticle> bNews = new List<NewsArticle>();
where NewsArticle is defined as:
public class NewsArticle : INotifyPropertyChanged
{
private string Description;
public event PropertyChangedEventHandler PropertyChanged;
public string Description1
{
get { return Description; }
set { Description = value; }
}
private string Link;
public string Link1
{
get { return Link; }
set { Link = value; }
}
private string Title;
public string Title1
{
get { return Title; }
set { Title = value;
NotifyProperyChanged("Title");
}
}
public void NotifyProperyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
And here is the XAML showing my HubSection and my bindings.
<HubSection DataContext="{Binding bNews}" Name="newsHub" Header="Hello World">
<DataTemplate>
<ListView ItemsSource="{Binding}" Margin="10" Name="ListBoxRss">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Title1}" Tag="{Binding Link1}" TextWrapping="Wrap" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</DataTemplate>
</HubSection>
I've looked around for other examples and was even able to get it to work properly in a Panorama style app but am having trouble getting it to work properly inside a HubSection. Any insight would be wonderful.

How to make binding to WPF TreeView?

I have a TreeView with Binding, but in the TreeView only 1st level items are shown. I need a treeview =) I broke my head what is wrong.
Here is my code:
MainWindow.xaml
<TreeView Margin="2.996,10,214,10" ItemsSource="{Binding Path=Urls}" Grid.Column="1">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate>
<Grid>
<Rectangle Fill="{Binding Path=Color}" HorizontalAlignment="Left" Stroke="Black" VerticalAlignment="Top" Height="20" Width="20"/>
<TextBlock Text="{Binding Path=AbsoluteUrl}" Margin="25,0,0,0" />
</Grid>
<HierarchicalDataTemplate.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=AbsoluteUrl}" />
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
MainViewModel.cs (part)
public ObservableCollection<Url> Urls { get; set; }
public MainWindowViewModel()
{
Urls = new ObservableCollection<Url>();
}
Url.cs
class Url : INotifyPropertyChanged
{
public Url() { }
public Url(string absoluteUrl, bool isBroken, string color)
{
AbsoluteUrl = absoluteUrl;
IsBroken = isBroken;
Color = color;
}
enum Status { Working, Broken };
private ObservableCollection<Url> childUrlsValue = new ObservableCollection<Url>();
public ObservableCollection<Url> ChildUrls
{
get
{
return childUrlsValue;
}
set
{
childUrlsValue = value;
}
}
private string _absoluteUrl;
public string AbsoluteUrl
{
get { return _absoluteUrl; }
set
{
if (_absoluteUrl != value)
{
_absoluteUrl = value;
OnPropertyChanged("AbsoluteUrl");
}
}
}
private bool _isBroken;
public bool IsBroken
{
get { return _isBroken; }
set
{
if (_isBroken != value)
{
_isBroken = value;
OnPropertyChanged("IsBroken");
}
}
}
private string _color;
public string Color
{
get { return _color; }
set
{
if (_color != value)
{
_color = value;
OnPropertyChanged("Color");
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
And just about this i'm adding items to Urls:
Url DataGridTopic = new Url(startUrl.ToString(), true, "red");
DataGridTopic.ChildUrls.Add(
new Url(startUrl.ToString(), true, "red"));
DataGridTopic.ChildUrls.Add(
new Url(startUrl.ToString(), true, "red"));
DataGridTopic.ChildUrls.Add(
new Url(startUrl.ToString(), true, "red"));
Urls.Add(DataGridTopic);

You will have to tell the HierarchicalDataTemplate where to get the child items of a node from by using its ItemsSource property.
In your case:
<HierarchicalDataTemplate
DataType="{x:Type my:Url}"
ItemsSource="{Binding Path=ChildUrls}"
>
...
</HierarchicalDataTemplate>
Note also the usage od the DataType attribute, which often will become a necessity if the levels of the tree are made of different object types (a tree of directories and files would be such an example). However, i am not sure whether this would apply to your scenario or not.

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.