Develop Reference

C# WPF ListView control - Problem with binding data

I'm having some trouble binding data to a ListView control. I watched many tutorials where it seems like they did it the way I did here with either binding to a collection or a class that had a collection of items.
When I add the cars in this example nothing is added to the listview control. Anything obvious I have missed here? I have checked that the cars are added to the collection during runtime.
The car class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace CarClasses
{
internal class Car
{
string _brand = "";
string _model = "";
public Car(string brand, string model)
{
_brand = brand;
_model = model;
}
public string Brand
{
get { return _brand; }
set { _brand = value; }
}
public string Model
{
get { return _model; }
set { _model = value; }
}
}
}
MainWindow.xaml:
<Window x:Class="GridViewListView.MainWindow"
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:local="clr-namespace:GridViewListView"
mc:Ignorable="d"
Title="MainWindow" Height="300" Width="600">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="75"></ColumnDefinition>
<ColumnDefinition Width="2*"></ColumnDefinition>
<ColumnDefinition Width="7*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<ListView x:Name="lvCarList" ItemsSource="{Binding CarCollection }" Grid.Column="2" Width="200" Height="250" SelectionMode="Single" BorderThickness="3" BorderBrush="AliceBlue">
<ListView.Style>
<Style/>
</ListView.Style>
<ListView.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50"></ColumnDefinition>
<ColumnDefinition Width="100"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" Content="{Binding Brand}"></Label>
<Label Grid.Row="0" Grid.Column="1" Content="{Binding Model}"></Label>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<StackPanel Grid.Column="0">
<TextBlock Text="Brand" Margin="10,10,0,0"></TextBlock>
<TextBlock Text="Model" Margin="10,10,0,0"></TextBlock>
</StackPanel>
<StackPanel Grid.Column="1" Margin="0,0,0,0">
<TextBox Name="txtBrand" HorizontalAlignment="Left" Width="100" Margin="10,10,0,0"></TextBox>
<TextBox Name="txtModel" HorizontalAlignment="Left" Width="100" Margin="10,10,0,0"></TextBox>
<Button Name="btnAdd" Content="Add" Margin="10, 10,10,10" Click="btnAdd_Click"></Button>
</StackPanel>
</Grid>
</Window>
MainWindow.xaml.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using CarClasses;
namespace GridViewListView
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
///
public partial class MainWindow : Window
{
List<Car> CarCollection = new List<Car>();
public MainWindow()
{
InitializeComponent();
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
Car newCar = new Car(txtBrand.Text, txtModel.Text);
CarCollection.Add(newCar);
txtBrand.Text = "";
txtModel.Text = "";
}
}
}

You should/need to specify the DataContext.
And you need to make the Car's collection a public property. It's currently a field.
And also it should be an ObservableCollection, because it's changed at runtime and changes should be displayed in the UI automatically.
public partial class MainWindow : Window
{
public ObservableCollection<Car> CarCollection { get; } = new ObservableCollection<Car>();
public MainWindow()
{
this.DataContext = this;
InitializeComponent();
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
Car newCar = new Car(txtBrand.Text, txtModel.Text);
CarCollection.Add(newCar);
txtBrand.Text = "";
txtModel.Text = "";
}
}

Model's property not recognized by xaml (WPF MVVM)

Using mvvmCross, .net (5.0), visual studio 19
View model:
using System.ComponentModel;
using System.Threading.Tasks;
using MvvmCross.ViewModels;
using MvxR_M_S.Core.API;
using MvxR_M_S.Core.Models;
namespace MvxR_M_S.Core.ViewModels
{
public class ArticlePresentationViewModel : MvxViewModel
{
public ArticlePresentationViewModel()
{
}
public override async void ViewAppeared()
{
base.ViewAppeared();
await LoadArticles(new ArticleEndpoint(new APIHelper()));
}
public async Task LoadArticles(ArticleEndpoint articleEndpoint)
{
var articleList = await articleEndpoint.GetAll();
Articles = new BindingList<ArticleModel>(articleList);
}
private BindingList<ArticleModel> _articles;
public BindingList<ArticleModel> Articles
{
get { return _articles; }
set
{
_articles = value;
SetProperty(ref _articles, value);
}
}
}
}
Model:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MvxR_M_S.Core.Models
{
public class ArticleModel
{
public string ArticleName { get; set; }
}
}
View:
<views:MvxWpfView
xmlns:views="clr-namespace:MvvmCross.Platforms.Wpf.Views;assembly=MvvmCross.Platforms.Wpf"
xmlns:mvx="clr-namespace:MvvmCross.Platforms.Wpf.Binding;assembly=MvvmCross.Platforms.Wpf"
x:Class="MvxR_M_S.Wpf.Views.ArticlePresentationView"
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:models="clr-namespace:MvxR_M_S.Core.Models;assembly=MvxR_M_S.Core"
xmlns:viewModels="clr-namespace:MvxR_M_S.Core.ViewModels;assembly=MvxR_M_S.Core"
mc:Ignorable="d" FontSize="20" Background="Wheat"
d:DesignHeight="450" d:DesignWidth="800">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="20" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="20" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="20" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="20" />
</Grid.RowDefinitions>
<TextBlock Grid.Column="1" Grid.ColumnSpan="2" Grid.Row="1" HorizontalAlignment="Center" Text="Article list" />
<ListBox x:Name="Articles" ItemsSource="{Binding Articles}" Grid.Column="2" Grid.Row="2" MinHeight="300" MinWidth="300" >
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ArticleName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</views:MvxWpfView>
The problem is at the listbox, where it references ItemsSource right, also i did debug at the Articles property inside ViewModel, it holds right information, but nothing is presented on screen when started up.
So i guess this is binding issue.

Remove _articles = value; in Articles setter. SetProperty doesn't do anything if the field already is set
public BindingList<ArticleModel> Articles
{
get { return _articles; }
set
{
SetProperty(ref _articles, value);
}
}

Since you are retrieving the articles in a separate thread, I think you have to do something like this:
Dispatcher.BeginInvoke(new Action(() => Articles = new BindingList<ArticleModel>(articleList);));
I am not exactly sure if it's the right way but Dispatcher.BeginInvoke seems needed from what I found

WPF Updating UI using Multiple Classes

I am teaching myself... I cannot understand why the UI won't update when a second class is involved. I am missing something basic and I don't get it.
In the first Class:
I have two ObservableCollections bound to two WPF ListViews, which is bound correctly and works.
I have a Command bound to a Button to move items from one Collection to the other, which works as expected.
In the second Class (backcode) I have implemented "Drag and Drop". On Drop I try to call the same Method (which is in the first Class and is used by the Button/Command. The Command is also in the first class).
On "Drag and Drop" the items are moved from one collection to the other (confirmed with Console.Writeline), however the UI doesn't update like it does with the Button/Command.
I believe the problem is that with "Drag and Drop" I am calling the Method from another class. I thought I could do that, but I must not be doing it right?
I have included everything from 4 files (xaml, backcode, class, relayCommand) so hopefully it is easy to reproduce. Can anyone tell me why & how to get this to work???
<Window x:Class="MultipleClassDragAndDrop.MainWindow"
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:local="clr-namespace:MultipleClassDragAndDrop"
xmlns:ViewModel="clr-namespace:MultipleClassDragAndDrop.ViewModel"
mc:Ignorable="d"
Title="MainWindow" Height="716" Width="500">
<Window.Resources>
<ViewModel:MultiColumnViewModel x:Key="MultiColumnViewModel"/>
</Window.Resources>
<Grid DataContext="{Binding Mode=OneWay, Source={StaticResource MultiColumnViewModel}}" >
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid Grid.Row="0" Grid.Column="0" >
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="700"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<StackPanel Grid.Row="0" Orientation="Vertical">
<Button Content="Test Command" Command="{Binding Test_Command}"/>
</StackPanel>
<ListView Grid.Row="1" Grid.Column="0" x:Name="ListView1" Background="Black" MinWidth="165" Width="Auto" HorizontalContentAlignment="Center"
ItemsSource="{Binding ActiveJobListView1, UpdateSourceTrigger=PropertyChanged}" MouseMove="ListView1_MouseMove" >
<ListView.ItemTemplate>
<DataTemplate>
<GroupBox BorderThickness="0" Foreground="Black" FontWeight="Bold" Width="150" Background="LightPink" BorderBrush="Transparent">
<StackPanel Orientation="Vertical" VerticalAlignment="Center" >
<TextBlock Text="{Binding JobID}" FontWeight="Bold" />
<TextBlock Text="{Binding CustomerName}" FontWeight="Bold" />
</StackPanel>
</GroupBox>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
<Grid Grid.Row="0" Grid.Column="2" >
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="700"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ListView Grid.Row="1" Grid.Column="0" x:Name="ListView2" Background="Black" MinHeight="300" MinWidth="165" Width="Auto" HorizontalContentAlignment="Center"
ItemsSource="{Binding ActiveJobListView2, UpdateSourceTrigger=PropertyChanged}"
MouseMove="ListView1_MouseMove"
AllowDrop="True" Drop="ListView2_Drop" >
<ListView.ItemTemplate>
<DataTemplate>
<GroupBox BorderThickness="0" Foreground="Black" FontWeight="Bold" Width="150" Background="LightBlue" BorderBrush="Transparent">
<StackPanel Orientation="Vertical" VerticalAlignment="Center" >
<TextBlock Text="{Binding JobID}" FontWeight="Bold" />
<TextBlock Text="{Binding CustomerName}" FontWeight="Bold" />
</StackPanel>
</GroupBox>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Grid>
BackCode
using MultipleClassDragAndDrop.ViewModel;
using System.Diagnostics;
using System.Windows;
using System.Windows.Input;
namespace MultipleClassDragAndDrop
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
MultiColumnViewModel objMultiColumnViewModel = new MultiColumnViewModel();
private void ListView1_MouseMove(object sender, MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.LeftButton == MouseButtonState.Pressed)
{
int lb_itemIndex = ListView1.SelectedIndex;
// Package the data.
DataObject data = new DataObject();
data.SetData("Int", lb_itemIndex);
data.SetData("Object", this);
// Inititate the drag-and-drop operation.
DragDrop.DoDragDrop(this, data, DragDropEffects.Move);
}
}
private void ListView2_Drop(object sender, DragEventArgs e)
{
Debug.WriteLine($"\n\n{System.Reflection.MethodBase.GetCurrentMethod()}");
base.OnDrop(e);
int index = (int)e.Data.GetData("Int");
// Call A Method In A Different Class
objMultiColumnViewModel.AddAndRemove(index);
e.Handled = true;
}
}
}
My ViewModel Class
using MultipleClassDragAndDrop.ViewModel.Commands;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Windows.Input;
namespace MultipleClassDragAndDrop.ViewModel
{
public class ActiveJob : INotifyPropertyChanged
{
#region INotifyPropertyChanged
//INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
Debug.WriteLine($"NOTIFY PROPERTY CHANGED! {info}");
}
}
#endregion
public string _JobID;
public string JobID
{
get { return _JobID; }
set
{ _JobID = value; NotifyPropertyChanged("JobID"); }
}
public string _CustomerName;
public string CustomerName
{
get { return _CustomerName; }
set
{ _CustomerName = value; NotifyPropertyChanged("CustomerName"); }
}
}
public partial class MultiColumnViewModel : INotifyPropertyChanged
{
#region INotifyPropertyChanged
//INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
Debug.WriteLine($"NOTIFY PROPERTY CHANGED! {info}");
}
}
#endregion
//Test Command
private ICommand _Test_Command;
public ICommand Test_Command
{
get
{
if (_Test_Command == null)
{
_Test_Command = new RelayCommand<object>(ExecuteTest_Command, CanExecuteTest_Command);
}
return _Test_Command;
}
}
public bool CanExecuteTest_Command(object parameter)
{
return true;
}
public void ExecuteTest_Command(object parameter)
{
Mouse.OverrideCursor = Cursors.Wait;
AddAndRemove(0);
Mouse.OverrideCursor = Cursors.Arrow;
}
public void AddAndRemove(int selectedIndex)
{
Debug.WriteLine($"\n\n{System.Reflection.MethodBase.GetCurrentMethod()} Index = {selectedIndex}\n");
ActiveJobListView2.Add(ActiveJobListView1[selectedIndex]);
ActiveJobListView1.RemoveAt(selectedIndex);
foreach (var item in ActiveJobListView1)
{
System.Console.WriteLine($"ActiveJobListView1: {item.JobID}, {item.CustomerName}");
}
System.Console.WriteLine($" ");
foreach (var item in ActiveJobListView2)
{
System.Console.WriteLine($"ActiveJobListView2: {item.JobID}, {item.CustomerName}");
}
}
public MultiColumnViewModel()
{
ActiveJobListView1 = new ObservableCollection<ActiveJob>();
ActiveJobListView2 = new ObservableCollection<ActiveJob>();
ActiveJobListView1.Add(new ActiveJob { JobID = "JOB100", CustomerName = "Smith" });
ActiveJobListView1.Add(new ActiveJob { JobID = "JOB101", CustomerName = "Jones" });
ActiveJobListView1.Add(new ActiveJob { JobID = "JOB102", CustomerName = "Black" });
}
#region Properties
private ObservableCollection<ActiveJob> _ActiveJobListView1;
public ObservableCollection<ActiveJob> ActiveJobListView1
{
get { return _ActiveJobListView1; }
set
{
_ActiveJobListView1 = value;
NotifyPropertyChanged("ActiveJobListView1");
}
}
private ObservableCollection<ActiveJob> _ActiveJobListView2;
public ObservableCollection<ActiveJob> ActiveJobListView2
{
get { return _ActiveJobListView2; }
set
{
_ActiveJobListView2 = value;
NotifyPropertyChanged("ActiveJobListView2");
}
}
#endregion
}
}

When binding to a Collection, there are 3 kinds of ChangeNotification you need:
The Notification that informs the UI if something was added or removed from the Collection. That is the only kind of Notification ObservableCollection provides.
The Notification on the property exposing the ObservableCollection. Due to case 1 binding and the lack of a "add range", it is a bad idea to do bulk-modifications of a exposed List. Usually you create a new list and only then Expose it to the UI. In your case those would be the properties "ActiveJobListView1" and it's kind.
The Notification on every property of every type exposed in the collection. That would be "ActiveJob" in your case.
Some of those are often forgotten, with Case 2 being the most common case. I wrote a small introduction into WPF and the MVVM pattern a few years back. maybe it can help you here: https://social.msdn.microsoft.com/Forums/vstudio/en-US/b1a8bf14-4acd-4d77-9df8-bdb95b02dbe2/lets-talk-about-mvvm?forum=wpf

You have issues with different instances of the same class.
Change:
MultiColumnViewModel objMultiColumnViewModel = new MultiColumnViewModel();
To:
var objMultiColumnViewModel = this.DataContext as MultiColumnViewModel;
and it should work
EDIT:
What you are doing is strongly against MVVM principals.
EDIT-2
I had to do some modification to you code to make it work:
In your XAML:
<Window.DataContext>
<local:MultiColumnViewModel/>
</Window.DataContext>
<Grid>
<Grid.RowDefinitions>
In your MainWindow.cs:
public MainWindow()
{
InitializeComponent();
objMultiColumnViewModel = this.DataContext as MultiColumnViewModel;
}
private MultiColumnViewModel objMultiColumnViewModel;

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?

Grouping in WPF

I am trying to modify an existing code which allows to add articles by rows and remove them wherever needed, the problem is that I am trying to find a way to group articles of the same category. So when the user adds a new article of DVD category, it will be directly added to that category (I tried to take some ideas from here, but with no success: http://msdn.microsoft.com/en-us/library/ff407126.aspx
This is the code behind data:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Collections.ObjectModel;
namespace WpfDataGridWithDataTable
{
public class Article
{
public Article ()
{
}
private int _modelNumber;
public int ModelNumber
{
get { return _modelNumber; }
set { _modelNumber = value; OnPropertyChanged("ModelNumber"); }
}
private string _modelName;
public string ModelName
{
get { return _modelName; }
set { _modelName = value; OnPropertyChanged("ModelName"); }
}
private decimal _unitCost;
public decimal UnitCost
{
get { return _unitCost; }
set { _unitCost = value; OnPropertyChanged("UnitCost"); }
}
private string _description ;
public string Description
{
get { return _description; }
set { _description = value; OnPropertyChanged("Description"); }
}
#region INotifyPropertyChanged Membres
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
}
#endregion
}
public class ListArticles : ObservableCollection<Article >
{
public Article a;
public ListArticles()
{
a = new Article();
this.Add(a);
}
}
}
And here is the XAML code:
<Window x:Class="WpfDataGridWithDataTable.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfDataGridWithDataTable"
Title="Window1" Height="300" Width="300">
<Grid
Name="gridPanel">
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<DataGrid
Grid.Column="0"
Name="dataGrid1"
AutoGenerateColumns="True"
CanUserAddRows="True"
CanUserDeleteRows="True"
CanUserResizeColumns="True"
IsSynchronizedWithCurrentItem="True"
ItemsSource="{Binding}"/>
<ListBox
Grid.Column="1"
Name="listBox1"
IsSynchronizedWithCurrentItem="True"
ItemsSource="{Binding}">
<ListBox.ItemTemplate>
<DataTemplate DataType="{x:Type local:Article}">
<StackPanel
Orientation="Horizontal">
<TextBlock
Width="100"
Margin="10"
Background="DarkBlue"
Foreground="White"
FontSize="14"
Text="{Binding ModelNumber}"/>
<TextBlock
Width="100"
Margin="10"
Background="DarkBlue"
Foreground="White"
FontSize="14"
Text="{Binding ModelName}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button
Grid.Row="1"
Grid.Column="0"
HorizontalAlignment="Left"
Width="100"
Name="btnAdd"
Content="Add Item"
Click="btnAdd_Click">
</Button>
<Button
Grid.Row="1"
Grid.Column="1"
HorizontalAlignment="Right"
Width="100"
Name="btnDelete"
Content="Delete Item"
Click="btnDelete_Click" >
</Button>
</Grid>
</Window>
And the code behind the form:
namespace WpfDataGridWithDataTable
{
/// <summary>
/// Logique d'interaction pour Window1.xaml
/// </summary>
public partial class Window1 : Window
{
private ListArticles myList;
public Window1()
{
InitializeComponent();
myList = new ListArticles();
this.DataContext = myList;
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
myList.Add(new Article());
}
private void btnDelete_Click(object sender, RoutedEventArgs e)
{
myList.Remove(this.dataGrid1.SelectedItem as Article);
}
}
}
Thanks for your answers.

I finally resolved the problem, but I don't know why it didn't worked. The issue was located in the XAML code when binding the datagrid with the CollectionViewSource. I put:
<DataGrid Name="dataGrid1"
AutoGenerateColumns="True"
CanUserAddRows="True"
CanUserDeleteRows="True"
CanUserResizeColumns="True"
IsSynchronizedWithCurrentItem="True"
Grid.ColumnSpan="2"
ItemsSource="{Binding Source={StaticResource cvsListArticles}}">
The last line was the problem, when I simply put ItemsSource="{Binding}" it finally worked.
Here is the code for those who might have the same problem and want to benefit from it:
code behind data:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Collections.ObjectModel;
namespace WpfDataGridWithDataTable
{
public class Article
{
public Article()
{
}
private int _modelNumber;
public int ModelNumber
{
get { return _modelNumber; }
set { _modelNumber = value; OnPropertyChanged("ModelNumber"); }
}
private string _modelName;
public string ModelName
{
get { return _modelName; }
set { _modelName = value; OnPropertyChanged("ModelName"); }
}
private decimal _unitCost;
public decimal UnitCost
{
get { return _unitCost; }
set { _unitCost = value; OnPropertyChanged("UnitCost"); }
}
private string _description;
public string Description
{
get { return _description; }
set { _description = value; OnPropertyChanged("Description"); }
}
#region INotifyPropertyChanged Membres
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
}
#endregion
}
public class ListArticles : ObservableCollection<Article>
{
public Article a;
public ListArticles()
{
a = new Article();
this.Add(a);
}
}
}
The XAML code:
<Window x:Class="WpfDataGridWithDataTable.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication18"
Title="Window1" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" Height="480" Width="760">
<Window.Resources>
<CollectionViewSource x:Key="cvsListArticles" Source="Article">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="ModelName"/>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</Window.Resources>
<Grid
Name="gridPanel">
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<DataGrid Name="dataGrid1"
AutoGenerateColumns="True"
CanUserAddRows="True"
CanUserDeleteRows="True"
CanUserResizeColumns="True"
IsSynchronizedWithCurrentItem="True"
ItemsSource="{Binding}" Grid.ColumnSpan="2" >
<DataGrid.GroupStyle>
<GroupStyle>
<GroupStyle.ContainerStyle>
<Style TargetType="{x:Type GroupItem}">
<Setter Property="Margin" Value="0,0,0,5"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupItem}">
<Expander IsExpanded="True" Background="#FF112255" BorderBrush="#FF002255" Foreground="#FFEEEEEE" BorderThickness="1,1,1,5">
<Expander.Header>
<DockPanel>
<TextBlock FontWeight="Bold" Text="{Binding Path=Name}" Margin="5,0,0,0" Width="100"/>
</DockPanel>
</Expander.Header>
<Expander.Content>
<ItemsPresenter />
</Expander.Content>
</Expander>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>
</DataGrid.GroupStyle>
</DataGrid>
<Button
Grid.Row="1"
Grid.Column="0"
HorizontalAlignment="Left"
Width="100"
Name="btnAdd"
Content="Add Item"
Click="btnAdd_Click">
</Button>
<Button
Grid.Row="1"
Grid.Column="1"
HorizontalAlignment="Right"
Width="100"
Name="btnDelete"
Content="Delete Item"
Click="btnDelete_Click" >
</Button>
<Button Content="Group" Grid.ColumnSpan="2" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="294,5,0,0" Name="GroupButton" VerticalAlignment="Top" Width="145" Click="GroupButton_Click" />
</Grid>
</Window>
The code behind the form:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Collections.ObjectModel;
using System.ComponentModel;
namespace WpfDataGridWithDataTable
{
public partial class Window1 : Window
{
private ListArticles myList;
public Window1()
{
InitializeComponent();
myList = new ListArticles();
this.DataContext = myList;
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
myList.Add(new Article());
}
private void btnDelete_Click(object sender, RoutedEventArgs e)
{
myList.Remove(this.dataGrid1.SelectedItem as Article);
}
private void GroupButton_Click(object sender, RoutedEventArgs e)
{
ICollectionView cvsListArticles = CollectionViewSource.GetDefaultView(dataGrid1.ItemsSource);
if (cvsListArticles != null && cvsListArticles.CanGroup == true)
{
cvsListArticles.GroupDescriptions.Clear();
cvsListArticles.GroupDescriptions.Add(new PropertyGroupDescription("ModelName"));
}
}
}
}