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WPF After ICommand INotifyPropertyChanged is called, but not updating UI [MVVM]

When the View is initialized, their standard value "VM", definied in the ViewModel, is updated trough the Model and updated in the View. However, when the ICommand NavigationCommand is triggered, the code in the OnNavigationCommand method executes, and even the OnPropertyChanged (INotifyPropertyChanged) method is called in the Model. However, the textboxes in the UI still remains the same value: "VM". I have tried a lot, but can't seem to find the problem. Hope you can help.
View
<vw:View xmlns:cc="clr-namespace:HMI.CustomControl" xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
x:Class="HMI.ZoneFView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:vw="http://inosoft.com/visiwin7"
xmlns:main="clr-namespace:HMI.Views.MainRegion"
xmlns:local="clr-namespace:HMI" xmlns:dialogregion="clr-namespace:HMI.Views.DialogRegion"
mc:Ignorable="d"
DataContext="{vw:AdapterBinding ViewModel}">
<Viewbox>
<Grid x:Name="LayoutRoot" Width="140" Height="220.5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="3"/>
<ColumnDefinition Width="5*"/>
<ColumnDefinition Width="3"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="5" />
<RowDefinition Height="5*" />
<RowDefinition Height="5" />
</Grid.RowDefinitions>
<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding theModel.VisibilityFFUView}" Margin="57,16,7,62" />
<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding theModel.VisibilityFFUView}" Margin="57,48,7,30" />
</Grid>
</Viewbox>
</vw:View>
View.cs
using HMI.Views.MainRegion;
using VisiWin.ApplicationFramework;
namespace HMI
{
[ExportView("ZoneFView")]
public partial class ZoneFView : VisiWin.Controls.View
{
public ZoneFView()
{
this.InitializeComponent();
}
}
}
ViewModel
using System;
using System.ComponentModel.Composition;
using System.Windows.Input;
using VisiWin.ApplicationFramework;
using VisiWin.Commands;
namespace HMI.Views.MainRegion
{
[ExportAdapter("ViewModel")]
[PartCreationPolicy(CreationPolicy.NonShared)]
class ViewModel : AdapterBase
{
#region Constructor
public Model Model { get; set; }
public ViewModel()
{
// If the VisiWin system is not in the runtime, the VW7 functionalities cannot be accessed
if (ApplicationService.IsInDesignMode)
{
return;
}
// Create the Action Commands
this.NavigationCommand = new ActionCommand(OnNavigationCommand);
Model = new Model()
{
VisibilityFFUView = "VM"
};
}
#endregion
#region CordisAdapterBase implementation
// Called when the view on which this adapter is located as DataContext is loaded
public override void OnViewAttached(IView view)
{
base.OnViewAttached(view);
}
public override void OnViewDetached(IView view)
{
base.OnViewDetached(view);
}
#endregion
#region NavigationCommand - Command from the view into the ViewModel
public ICommand NavigationCommand { get; set; }
// NavigationCommand event call
// Will be called if one of the buttons in the "AppbarView" view is clicked.
// The command of the model is linked to the button via the Command property.
private void OnNavigationCommand(object commandParameter)
{
if (commandParameter != null)
{
if (ApplicationService.IsInDesignMode) return;
string strParameter = commandParameter.ToString();
switch (strParameter)
{
case "FFU":
Model.VisibilityFFUView = "Turn on";
break;
case "FFUswitch":
Model.VisibilityFFUView = "Turn off";
break;
default:
break;
}
}
else
{
throw new ArgumentNullException(nameof(commandParameter));
}
}
#endregion
}
}
Model
using System.ComponentModel.Composition;
using VisiWin.ApplicationFramework;
namespace HMI.Views.MainRegion
{
[ExportAdapter("Model")]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class Model : ObserverableObject
{
private string _visibilityFFUView;
public string VisibilityFFUView
{
get { return _visibilityFFUView; }
set
{
_visibilityFFUView = value;
OnPropertyChanged();
}
}
}
}
ObserverableObject
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace HMI.Views.MainRegion
{
public class ObserverableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
UPDATE
I have added the NavigationView, and shifted both the DataContext of NavigationView and ZoneFView to XAML to reduce some code..
NavigationView
<vw:View xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
x:Class="HMI.Views.Common.AppbarView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:vw="http://inosoft.com/visiwin7" xmlns:local="clr-namespace:HMI"
mc:Ignorable="d" d:DesignWidth="200" d:DesignHeight="638"
DataContext="{vw:AdapterBinding ViewModel}">
<Grid x:Name="LayoutRoot" Background="{DynamicResource AppbarBackgroundBrush}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="8" />
</Grid.ColumnDefinitions>
<Rectangle Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Fill="{DynamicResource AccentBrush}" StrokeThickness="0" />
<StackPanel Grid.Column="0" Margin="10,10,0,0" VerticalAlignment="Top">
<vw:NavigationRadioButton HorizontalAlignment="Stretch" RegionName="MainRegion" ViewName="HomeView" IsChecked="True" Style="{DynamicResource AppbarNavigationRadioButtonStyle}" VerticalAlignment="Top" Height="52" Symbol="{DynamicResource appbar.tiles.nine}" LocalizableText="#Appbar.Dashboard" Margin="0,0,0,0" SymbolHorizontalAlignment="Left" />
<vw:NavigationRadioButton HorizontalAlignment="Stretch" RegionName="MainRegion" ViewName="FFUnitsView" IsChecked="false" Style="{DynamicResource AppbarNavigationRadioButtonStyle}" VerticalAlignment="Top" Height="52" Symbol="{DynamicResource appbar.interface.button}" LocalizableText="#Appbar.FFUnits" Margin="0,10,0,0" BorderThickness="1,1,0,1" CommandParameter="FFU" Command="{Binding NavigationCommand}">
</vw:NavigationRadioButton>
</StackPanel>
</Grid>
</vw:View>
Solution:
Like Clemens said I did use two instances of my DataContext. Therefore, when I did updated my property
I found this post on how to solve this problem: How can I create only one instance of a DataContext for multiple windows? Thanks for the input! Case closed.

How to update data in a new non-modal window after changing the selection to ListView?

I have a user list in MainWindow. After pressing the preview button, a non-modal window for data editing opens. Updated data are changed in real time in the main window. The question is how to bind the windows so that because the user changes from the list in the main window, he changes in real time in an already open non-modal window.

WPF does not recommend coding business logic directly in xaml.cs
files.
It is recommended that you write code using the MVVM pattern
ViewModel
public class podgladUzytkownika : INotifyPropertyChanged
{
private string imie;
private string nazwisko;
private string mail;
public string Mail
{
get => mail;
set => this.SetValue(ref mail, value);
}
public string Nazwisko
{
get => nazwisko;
set => this.SetValue(ref nazwisko, value);
}
public string Imie
{
get => imie;
set => this.SetValue(ref imie, value);
}
public event PropertyChangedEventHandler PropertyChanged;
protected void SetValue<T>(ref T oldValue, T newValue, [CallerMemberName] string propertyName = null)
{
oldValue = newValue;
OnPropertyChanged(propertyName);
}
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
public class MainWindowViewModel
{
private int refreshCount;
public ICommand RefreshCommand { get; }
public ICommand PodgladUzytkownikaShow { get; }
public podgladUzytkownika data { get; }
public MainWindowViewModel()
{
data = new podgladUzytkownika();
PodgladUzytkownikaShow = new Command(PodgladUzytkownikaShowExecute);
RefreshCommand = new Command(RefreshCommandExecute);
}
private void PodgladUzytkownikaShowExecute(object obj)
{
var window = new Window();
window.DataContext = data;
window.Show();
}
private void RefreshCommandExecute(object obj)
{
// Data updates are passed to the view
refreshCount++;
data.Imie = nameof(data.Imie) + refreshCount;
data.Nazwisko = nameof(data.Nazwisko) + refreshCount;
data.Mail = nameof(data.Mail) + refreshCount;
}
}
View
// MainWindow.xaml
<StackPanel x:Name="StackPanel1">
<Button Content="PodgladUzytkownika" Command="{Binding Path=PodgladUzytkownikaShow}"/>
<Button Content="Refresh" Command="{Binding Path=RefreshCommand}"/>
</StackPanel>
// window.xaml
<StackPanel >
<TextBlock Text="{Binding Path=Imie }"/>
<TextBlock Text="{Binding Path=Nazwisko }"/>
<TextBlock Text="{Binding Path=Mail }"/>
</StackPanel>
Demo
this.MainWindow.DataContext =new MainWindowViewModel();

After chasing one problem after another with your comments, the problem is your code is not well-designed. Using data bindings (one of the prime benefits of WPF), you can stop chasing your tail with trying to figure out how to update one UI when data changes. Here is a simplified version of your code that will always ensure the UI matches the data you wish to manipulate.
MainWindow.xaml
<Grid Margin="3">
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="auto"/>
</Grid.ColumnDefinitions>
<Label Margin="3" Grid.ColumnSpan="3">Lista użytkowników</Label>
<Button Margin="3" Padding="3" Grid.Row="2" Grid.ColumnSpan="3" Click="Zamknij_Click">Zamknij</Button>
<StackPanel Margin="3" Grid.Column="2" Grid.Row="1">
<!--<Button Name="Dodaj" Click="Dodaj_Click" Margin="3" Padding="10,3" >Dodaj...</Button>-->
<!--<Button Name="Usun" IsEnabled="False" Click="Usun_Click" Margin="3" Padding="10,3" >Usuń</Button>-->
<!--<Button Name="Edytuj" IsEnabled="False" Click="Edytuj_Click" Margin="3" Padding="10,3" >Edytuj...</Button>-->
<Button Name="Podglad" IsEnabled="False" Click="Podglad_Click" Margin="3" Padding="10,3" >Podgląd...</Button>
</StackPanel>
<ListView SelectionMode="Single" SelectionChanged="Selection_Changed" Name="lv_uzytkownicy" Margin="3" Grid.Row="1">
<ListView.View>
<GridView>
<GridView.Columns>
<GridViewColumn Header="Imię"
DisplayMemberBinding="{Binding Imie}"/>
<GridViewColumn Header="Nazwisko"
DisplayMemberBinding="{Binding Nazwisko}" />
<GridViewColumn Header="Mail"
DisplayMemberBinding="{Binding Mail}"/>
</GridView.Columns>
</GridView>
</ListView.View>
</ListView>
<GridSplitter Grid.Column="1" Grid.Row="1" Width="5" ResizeDirection="Columns" HorizontalAlignment="Center"/>
</Grid>
MainWindow.xaml.cs
using System.Collections.ObjectModel;
public partial class MainWindow : Window
{
public ObservableCollection<Uzytkownik> listaUzytkownikow = new ObservableCollection<Uzytkownik>();
Podglad_Uzytkownika podgladUzytkownika;
public MainWindow()
{
InitializeComponent();
lv_uzytkownicy.ItemsSource = listaUzytkownikow;
listaUzytkownikow.Add(new Uzytkownik("Mietek", "Żul", "sikalafa#wp.pl"));
listaUzytkownikow.Add(new Uzytkownik("Franek", "Alpinista", "halo#gmail.pl"));
listaUzytkownikow.Add(new Uzytkownik("Stefan", "Ulążka", "mam.to#o2.pl"));
this.DataContext = this;
}
private void Podglad_Click(object sender, RoutedEventArgs e)
{
podgladUzytkownika = new Podglad_Uzytkownika();
podgladUzytkownika.DataContext = lv_uzytkownicy.SelectedItem;
podgladUzytkownika.Show();
}
private void Zamknij_Click(object sender, RoutedEventArgs e)
{
Close();
}
private void Selection_Changed(object sender, SelectionChangedEventArgs e)
{
if (lv_uzytkownicy.SelectedItems.Count > 0) Podglad.IsEnabled = true;
else Podglad.IsEnabled = false;
if (podgladUzytkownika != null && podgladUzytkownika.IsVisible)
{
podgladUzytkownika.DataContext = lv_uzytkownicy.SelectedItem;
}
}
}
Podglad_Uzytkownika.xaml
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Label Margin="3">Imię</Label>
<Label Margin="3" Grid.Row="1">Nazwisko</Label>
<Label Margin="3" Grid.Row="2">Email</Label>
<TextBox Name="imieTextBox" Text="{Binding Imie, UpdateSourceTrigger=PropertyChanged}" Margin="3" Grid.Column="1"/>
<TextBox Name="nazwiskoTextBox" Text="{Binding Nazwisko, UpdateSourceTrigger=PropertyChanged}" Margin="3" Grid.Column="1" Grid.Row="1"/>
<TextBox Name="mailTextBox" Text="{Binding Mail, UpdateSourceTrigger=PropertyChanged}" Margin="3" Grid.Column="1" Grid.Row="2"/>
<Grid HorizontalAlignment="Center" Grid.ColumnSpan="2" Grid.Row="3" Grid.IsSharedSizeScope="True">
<Grid.ColumnDefinitions>
<ColumnDefinition SharedSizeGroup="pierwsza" />
</Grid.ColumnDefinitions>
<Button Margin="3" Padding="20, 5" Name="Podglad" Click="Podglad_Click" IsDefault="True">Zamknij</Button>
</Grid>
</Grid>
Podglad_Uzytkownika.xaml.cs
public partial class Podglad_Uzytkownika : Window
{
public Podglad_Uzytkownika()
{
InitializeComponent();
}
private void Podglad_Click(object sender, RoutedEventArgs e)
{
Close();
}
}
Uzytkownik.cs
public class Uzytkownik : INotifyPropertyChanged
{
private string imie;
private string nazwisko;
private string mail;
public Uzytkownik(string imie, string nazwisko, string mail)
{
this.Imie = imie;
this.Nazwisko = nazwisko;
this.Mail = mail;
}
public string Imie { get => this.imie; set { this.imie = value; OnPropertyChanged(); } }
public string Nazwisko { get => this.nazwisko; set { this.nazwisko = value; OnPropertyChanged(); } }
public string Mail { get => this.mail; set { this.mail = value; OnPropertyChanged(); } }
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}

ObservableCollection not updated to UI when property changed

Question: ObservableCollection not updated to UI when property changed
What I have tried:
XAML view:
<UserControl x:Class="FlexilineDotNetGui.Flexiline.UserControls.UCRealestate"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
xmlns:translations="clr-namespace:FlexilineDotNetGui.Flexiline.Translations"
xmlns:viewModels="clr-namespace:FlexilineDotNetGui.Flexiline.ViewModels"
x:Name="Realestate"
DataContext="{StaticResource vmRealestate}">
<Grid Margin="5">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0" >
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<DataGrid Grid.Row="0" Grid.RowSpan="3" Grid.Column="0" Height="200" Margin="5"
ItemsSource="{Binding Panden, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" AutoGenerateColumns="False"
CanUserAddRows="False" IsReadOnly="True" SelectedItem="{Binding Pand}">
<DataGrid.Columns>
<DataGridTextColumn Header="{x:Static translations:UCRealestate.RegistrationType}" Binding="{Binding RegistrationType, Mode=TwoWay}" Width="Auto"/>
</DataGrid.Columns>
</DataGrid>
<Button Grid.Column="1" Grid.Row="0" Background="Transparent"
Width="20" Height="20" Padding="0" Margin="5" Command="{Binding AddPandCMD}"
CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type viewModels:RealestateViewModel}}}">
<Image Source="/Flexiline;component/Resources/New_16x16.ico"/>
</Button>
<Button Grid.Row="1" Grid.Column="1" VerticalAlignment="Top"
Width="20" Height="20" Padding="0" Background="Transparent" Margin="5" Command="{Binding DeletePandCMD}"
CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type viewModels:RealestateViewModel}}}">
<Image Source="/Flexiline;component/Resources/Delete_16x16.ico"/>
</Button>
<Grid Grid.Row="3" Margin="5">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid Grid.Row="1" Grid.Column="1" Margin="0,5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" MaxWidth="100"/>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
</Grid>
<Label Grid.Row="2" Grid.Column="2" Content="{x:Static translations:UCRealestate.RegistrationType}" HorizontalContentAlignment="Right" VerticalAlignment="Center"/>
<ComboBox Grid.Row="2" Grid.Column="3" Margin="5" ItemsSource="{Binding AardInschrijving, UpdateSourceTrigger=PropertyChanged}" SelectedValue="{Binding SelectedAardInschrijving, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="Description" SelectedValuePath="FlexKey"/>
</Grid>
</Grid>
</Grid>
</Grid>
</Grid>
</UserControl>
ViewModel :
using FlexilineDotNet.SharedDomainLogic.Models.CommunicationModels;
using FlexilineDotNetGui.Domain.Controls;
using FlexilineDotNetGui.Domain.Models;
using GalaSoft.MvvmLight.Command;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Data;
namespace FlexilineDotNetGui.Flexiline.ViewModels
{
public class RealestateViewModel : ANavigationPaneSubViewModel, INotifyPropertyChanged
{
BorgRealestate _borgRealestate = new BorgRealestate();
ObservableCollection<BorgRealestate> ocPanden = new ObservableCollection<BorgRealestate>();
private DomainController _controller = DomainController.GetInstance();
public RelayCommand<object> AddPandCMD { get; private set; }
public RelayCommand<object> DeletePandCMD { get; private set; }
#region "properties"
public ObservableCollection<BorgRealestate> Panden
{
get
{
return ocPanden ?? (ocPanden = new ObservableCollection<BorgRealestate>());
}
set
{
if (ocPanden == value)
return;
ocPanden = value;
OnPropertyChanged("Panden");
}
}
//public ObservableCollection<BorgRealestate> Panden { get; }
public BorgRealestate Pand
{
get
{
return _borgRealestate ?? (_borgRealestate = new BorgRealestate());
}
set
{
if (value == _borgRealestate) return;
_borgRealestate = value;
OnPropertyChanged();
OnPropertyChanged("Panden");
}
}
public List<DropDownItem> AardInschrijving { get { return _controller.GetDropDownItemsByType("AardInschrijving"); } }
private DropDownItem SelectedAardInschrijvingDI
{
get
{
DropDownItem test = _controller.GetDropDownItemsByType("AardInschrijving").FirstOrDefault(x => x.FlexKey == _borgRealestate?.RegistrationType);
if (test == null)
{
test = _controller.GetDropDownItemsByType("AardInschrijving").FirstOrDefault();
}
return test;
}
set
{
OnPropertyChanged();
OnPropertyChanged("Panden");
}
}
public int SelectedAardInschrijving
{
get
{
return SelectedAardInschrijvingDI.FlexKey;
}
set
{
if (value == Pand?.RegistrationType) return;
Pand.RegistrationType = value;
OnPropertyChanged();
OnPropertyChanged("Panden");
}
}
public string SelectedAardInschrijvingText
{
get
{
return SelectedAardInschrijvingDI.Description;
}
}
#endregion
#region "ctor"
public RealestateViewModel()
{
//Panden = new ObservableCollection<BorgRealestate>();
AddPandCMD = new RelayCommand<object>(o => AddPand());
DeletePandCMD = new RelayCommand<object>(o => DeletePand());
}
#endregion
#region "methods"
private void AddPand()
{
BorgRealestate newBorgRealestate = new BorgRealestate { RegistrationType = SelectedAardInschrijving };
Panden.Add(newBorgRealestate);
}
private void DeletePand()
{
Panden.Remove(Pand);
}
#endregion
}
}
Problem description:
When I Update the combobox value, it's updated in the "Panden" property when I check with a breakpoint but the datagrid in the view is not updated. The problem exists with Oneway and also with TwoWay as I defined in datagrid columns. I have both modes tried.
The views are inside a dxnavbar control, when I switch between navbar items and back then the view is updated OK.
EDIT:
When the application starts, the Panden list is indeed null, I had forgotten to mention something....
In my view there is a datagrid with a button where I add items to the observable collection where also some of the properies as example nature inscription combobox value is shown in datagrid. This button is then connected to a relay command. That is the collection that i have binded to the datagridview.
the getter of the property property is not empty and is therefore filled with the correct values, only the changes do not change in the view.
it is indeed normal that the collection is null if no "Pand" items are added to the "Panden" collection via the provided button on the UI (relaycommand). But the "Pand" item in de datagrid will not update after i change a value from the combobox after adding an item with the button to the collection.
EDIT 21/11 08:54
This is the logic for adding the pand:
private void AddPand()
{
BorgRealestate newBorgRealestate = new BorgRealestate { RegistrationType = SelectedAardInschrijving };
Panden.Add(newBorgRealestate);
}
But after i add i see the items gets added to the collection and get also updated in the collection after the combobox value changed only not in ui. (when the row in the datagrid have the focus)

In this code here:
public ObservableCollection<BorgRealestate> Panden
{
get
{
return ocPanden ?? (ocPanden = new ObservableCollection<BorgRealestate>());
}
You create a new collection but you don't at that point call OnPropertyChanged; and you shouldn't because it would be wrong to do this here. Therefore, the UI doesn't know you've created the new collection. It looks like the first time the above getter is called is in your AddPand function. Therefore, the UI never receives an OnPropertyChanged for Panden and so does not update.
Instead of this create the collection in your constructor and you should find it will update. Also you may not need a setter at all for Panden if it is never recreated.
in constructor:
Panden = new ObservableCollection<BorgRealestate>();
Then Panden property becomes:
public ObservableCollection<BorgRealestate> Panden { get; }
Which can be simplified to:
public ObservableCollection<BorgRealestate> Panden { get; } = new ObservableCollection<BorgRealestate>();

In the Viewmodel:
That short piece of code did the trick:
CollectionViewSource.GetDefaultView(ocPanden).Refresh();
Replace this:
public ObservableCollection<BorgRealestate> Panden
{
get
{
return ocPanden ?? (ocPanden = new ObservableCollection<BorgRealestate>());
}
set
{
if (ocPanden == value)
return;
ocPanden = value;
OnPropertyChanged("Panden");
}
}
With this:
public ObservableCollection<BorgRealestate> Panden
{
get
{
if(ocPanden != null)
{
CollectionViewSource.GetDefaultView(ocPanden).Refresh(); //This will do the trick
}
return ocPanden ?? (ocPanden = new ObservableCollection<BorgRealestate>());
}
set
{
if (ocPanden == value)
return;
ocPanden = value;
OnPropertyChanged("Panden");
}
}
Unfortunately I have not yet found out where the cause really comes from?
If someone can know that then leave a message?

Binding in WPF ListBox not updating TextBox, when data is changed

I have a list of buildings. Buildings have their own class (core), and are saved in an ObservableCollection. Building are displayed in the list, but when I change a variable which is visible in the list, that variable doesn't change in xaml.
Here is the source of class:
public class core
{
// core ----------------------------------------------
static public ObservableCollection<core> cores { get; set; } = new ObservableCollection<core>();
string namef = "building";
public core()
{
cores.Add(this);
}
public string Namef
{
get { return namef; }
set { namef = value; }
}
}
In wpf - xaml:
<Page x:Class="idle.pages.game"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:idle.pages"
mc:Ignorable="d"
d:DesignHeight="454.259" d:DesignWidth="757.012"
Title="game">
<Grid Margin="0" x:Name="gridx">
<Grid.RowDefinitions>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TabControl x:Name="tabControl">
<TabItem Header="Budovy">
<Grid Background="#FFE5E5E5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="300"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<ListBox x:Name="listBox">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="10,7" HorizontalAlignment="Stretch" Height="100">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Border Grid.Column="0" Grid.Row="0" Grid.RowSpan="3" CornerRadius="2"/>
<TextBlock Grid.Column="1" Grid.Row="0" Text="{Binding Namef}" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Frame x:Name="frame" Content="Frame" Grid.Column="1" NavigationUIVisibility="Hidden" Source="/idle;component/pages/Building.xaml"/>
</Grid>
</TabItem>
</TabControl>
</Grid>
and in wpf - c#:
public partial class game : Page
{
public game()
{
InitializeComponent();
new core() { Namef = "b1"};
new core() { Namef = "b2"};
new core() { Namef = "b3"};
core.start(this);
listBox.ItemsSource = xxx;
}
public ObservableCollection<core> xxx { get; set; }
}
Im sure, that the variable inside of the class is being changed, but xaml not. What's wrong?

You need to implement the INotifyPropertyChanged interface and invoke the PropertyChanged event in the setters of all properties that can change (and you want to have updated in the UI). If for example you want to see changes to Namef, you'd have to implement it like this:
public class core : INotifyPropertyChanged
{
static public ObservableCollection<core> cores { get; set; }
= new ObservableCollection<core>();
string namef = "building";
public core()
{
cores.Add(this);
}
public string Namef
{
get { return namef; }
set
{
if(namef == value) return;
namef = value;
OnPropertyChanged("Namef");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(String propertyName)
{
if (PropertyChanged == null) return;
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}

How do you to Add The Contents of Two TextBoxes Together and Display in a TextBlock

I'm dynamically create two textboxes and a textblock. The user first clicks a button which adds a row of controls and then inputs numbers in each textbox. The sum of the two boxes for a given row will be displayed in a text block.
Here is the XAML.
<Window x:Class="ModelBuilder_080614.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:ModelBuilder_080614"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<!-- this is a comment -->
<local:MainWindowViewModel />
</Window.DataContext>
<Canvas>
<Button Canvas.Top="21" Canvas.Left="20" Content="Add TextBox" Command="{Binding TestCommand}"/>
<ItemsControl Canvas.Top="50" Canvas.Left="50" ItemsSource="{Binding SomeCollection}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<TextBox Grid.Column="0" Grid.Row="0" Text="{Binding Path=.}"/>
<TextBox Grid.Column="1" Grid.Row="0" Name="Bench" Text="{Binding Path=.}"/>
<TextBlock Grid.Column="2" Grid.Row="0" Text="{Binding <!-- I'm LOST -->}"/>
<!-- I want this TextBlock to sum the Two TextBlocks -->
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Canvas>
</Window>
And here is my Model and ViewModel in C#.
using System;
using System.ComponentModel;
using System.Windows.Input;
using System.Collections.ObjectModel;
using System.Windows.Controls;
using System.Windows.Data;
using MicroMvvm;
namespace ModelBuilder_080614
{
public class MainWindowViewModel
{
public ObservableCollection<Model> SomeCollection { get; set; }
public ICommand TestCommand { get; private set; }
public MainWindowViewModel()
{
SomeCollection = new ObservableCollection<Model>();
TestCommand = new RelayCommand<object>(CommandMethod);
}
private void CommandMethod(object parameter)
{
SomeCollection.Add(new Model());
}
}
public class Model : INotifyPropertyChanged
{
double _actual;
double _bench;
double _active;
public double Actual
{
get { return _actual; }
set { _actual = value; }
}
public double Bench
{
get { return _bench; }
set { _bench = value; }
}
public double Active
{
get { return _active; }
set { _active = Actual - Bench; }
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
How do you bind the contents of the textboxes to display the sum of them in the TextBlock?

Bind to the properties in your ViewModel: (I removed the grid settings to make the example clearer)
<TextBox Text="{Binding Path=Actual, UpdateSourceTrigger=PropertyChanged}" />
<TextBox Text="{Binding Path=Bench, UpdateSourceTrigger=PropertyChanged" />
<TextBlock Text="{Binding Path=Active" />
Then when your values change, raise the notification on the "Active" property so it updates. You only need a "getter" on the "Active" property... when you call OnPropertyChanged(), it will perform the calculation and update the field for you.
double _actual;
double _bench;
public double Actual
{
get { return _actual; }
set
{
_actual = value;
OnPropertyChanged("Active");
}
}
public double Bench
{
get { return _bench; }
set
{
_bench = value;
OnPropertyChanged("Active");
}
}
public double Active
{
get { return Actual - Bench; }
}