C# WPF Binding to indexed property - what am I doing wrong?

C# WPF Binding to indexed property - what am I doing wrong? - c#

I have recently discovered indexed properties. This looks like the perfect solution to the scenario in which the data I am working with would best be expressed in a collection, yet still needs to be implemented as a property that can be used in XAML databinding. I started with just a test of creating indexed properties, and I had no problems there, but I just don't seem to be able to get the binding to work.
Can anyone point out where I'm going wrong?
Here is the test class with a nested class to create the indexed property:
public class TestListProperty
{
public readonly ListProperty ListData;
//---------------------------
public class ListProperty : INotifyPropertyChanged
{
private List<string> m_data;
internal ListProperty()
{
m_data = new List<string>();
}
public string this[int index]
{
get
{
if ( m_data.Count > index )
{
return m_data[index];
}
else
{
return "Element not set for " + index.ToString();
}
}
set
{
if ( m_data.Count > index )
{
m_data[index] = value;
}
else
{
m_data.Insert( index, value );
}
OnPropertyChanged( "Item[]" );
Console.WriteLine( value );
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged( string propertyName )
{
PropertyChangedEventHandler handler = PropertyChanged;
if ( handler != null ) handler( this, new PropertyChangedEventArgs( propertyName ) );
}
}
//---------------------------
public TestListProperty()
{
ListData = new ListProperty();
}
}
Here is the XAML:
<Window x:Class="TestIndexedProperties.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<TextBox Width="200" Grid.Row="0" Text="{Binding Path=ListData[0], Mode=TwoWay}" />
<TextBox Width="200" Grid.Row="1" Text="{Binding Path=ListData[1], Mode=TwoWay}" />
<TextBox Width="200" Grid.Row="2" Text="{Binding Path=ListData[2], Mode=TwoWay}" />
</Grid>
</Window>
And here is the Window code:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
TestListProperty test = new TestListProperty();
this.DataContext = test;
test.ListData[0] = "ABC";
test.ListData[1] = "Pleeez 2 wurk?";
test.ListData[2] = "Oh well";
}
}
Thanks for any and all help!

There's no mechanism in your code to indicate to the front-end when the list has changed, i.e. ListProperty is implementing INotifyPropertyChanged instead of INotifyCollectionChanged. The easiest fix would be to change m_data to type ObservableCollection and bind your XAML controls to that instead, although that probably defeats the purpose of what you're trying to do in the first place. The "proper" way is to subscribe to the CollectionChanged event and propagate the messages through:
public class TestListProperty
{
public ListProperty ListData { get; private set; }
//---------------------------
public class ListProperty : INotifyCollectionChanged
{
private ObservableCollection<string> m_data;
internal ListProperty()
{
m_data = new ObservableCollection<string>();
m_data.CollectionChanged += (s, e) =>
{
if (CollectionChanged != null)
CollectionChanged(s, e);
};
}
public string this[int index]
{
get
{
if (m_data.Count > index)
{
return m_data[index];
}
else
{
return "Element not set for " + index.ToString();
}
}
set
{
if (m_data.Count > index)
{
m_data[index] = value;
}
else
{
m_data.Insert(index, value);
}
Console.WriteLine(value);
}
}
public event NotifyCollectionChangedEventHandler CollectionChanged;
}
//---------------------------
public TestListProperty()
{
ListData = new ListProperty();
}
}

Related

WPF Combobox SelectedItem binding doesn't update from code

I have this combobox:
<ComboBox Grid.Column="1" SelectedItem="{Binding SelectedItem}" ItemsSource="{Binding Items, Mode=OneWay}" HorizontalAlignment="Stretch" VerticalAlignment="Center"/>
and this is the code:
public class CustomComboBoxViewModel
{
private bool DiscardSelChanged { get; set; }
public ObservableCollection<string> Items { get; set; }
public string SelectedItem
{
get { return _selectedItem; }
set
{
if (!DiscardSelChanged)
_selectedItem = value;
bool old = DiscardSelChanged;
DiscardSelChanged = false;
if (!old)
SelectionChanged?.Invoke(_selectedItem);
}
}
public event Action<string> SelectionChanged;
public void AddItem(string item)
{
var v = Items.Where(x => x.Equals(item)).FirstOrDefault();
if (v != default(string))
{
SelectedItem = v;
}
else
{
DiscardSelChanged = true;
_selectedItem = item;
Items.Insert(0, item);
}
}
}
At startup I have only one item: Browse.... selecting it i can browse for a file and add its path to the ComboBox. AddItem method is called
If the selected file path doesn't exists in Items i add and select it (this is working).
If the selected file path exists in Items i want to automatically select it without adding it to the list again. this doesn't work and Browse... is the visualized item.
I already tried to use INotifyPropertyChanged.
I'm using .NET 4.6.2. Any ideas to get it working?
EDIT 4:barebone example
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Windows;
namespace WpfApp2
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window, INotifyPropertyChanged
{
public MainWindow()
{
InitializeComponent();
DataContext = this;
Items = new ObservableCollection<string>();
Items.Add(ASD);
}
private string ASD = #"BROWSE";
private string _selectedItem;
public string SelectedItem
{
get { return _selectedItem; }
set
{
_selectedItem = value;
OnPropertyChanged(nameof(SelectedItem));
UploadFileSelection_SelectionChanged();
}
}
public ObservableCollection<string> Items { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName) =>
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
private void AddItem(string item)
{
var v = Items.Where(x => x.Equals(item)).FirstOrDefault();
if (v != default(string))
SelectedItem = v;
else
{
Items.Add(item);
SelectedItem = item;
}
}
private void UploadFileSelection_SelectionChanged()
{
if (SelectedItem == ASD)
{
Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog()
{
DefaultExt = ".*",
Filter = "* Files (*.*)|*.*"
};
bool? result = dlg.ShowDialog();
if (result == true)
AddItem(dlg.FileName);
}
}
}
}
comboBox:
<ComboBox SelectedItem="{Binding SelectedItem}" ItemsSource="{Binding Items}"/>
try to:
- select FILE_A.txt
- select FILE_B.txt
- select FILE_A.txt again

I tried your example. I fixed the re-entrancy problem (double browse dialog) with a flag:
private bool _browsing = false;
private void UploadFileSelection_SelectionChanged()
{
if (_browsing)
{
return;
}
if (SelectedItem == ASD)
{
try
{
_browsing = true;
Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog()
{
DefaultExt = ".*",
Filter = "* Files (*.*)|*.*"
};
bool? result = dlg.ShowDialog();
if (result == true)
AddItem(dlg.FileName);
}
finally
{
_browsing = false;
}
}
}
It's caveman stuff but it works.
The real problem you have is that UploadFileSelection_SelectionChanged() is called, and updates SelectedItem before you exit the SelectedItem setter from the call that sets it to ASD.
So SelectedItem = v; in AddItem() has no effect on the combobox, because the combobox isn't responding to PropertyChanged right then.
This will fix that:
private void AddItem(string item)
{
var v = Items.FirstOrDefault(x => x.Equals(item));
if (v != default(string))
{
//SelectedItem = v;
Task.Run(() => SelectedItem = v);
}
else
{
Items.Add(item);
SelectedItem = item;
}
}
Now we're doing it later.
But note that the other branch does work, the one where item is newly added to the collection. You can also fake it out by removing item and adding it again:
private void AddItem(string item)
{
// Harmless, if it's not actually there.
Items.Remove(item);
Items.Add(item);
SelectedItem = item;
}
That looks weirder, but since it doesn't rely on thread timing, it's probably a better solution. On the other hand, this is "viewmodel" code whose details are driven by the peculiarities of the implementation of the ComboBox control. That's not a good idea.
This should be probably be done in the view (leaving aside that in this contrived example our view is our viewmodel).

You are setting _selectedItem without calling OnPropertyChanged() afterwards. That's why it is not working. If you want a clear code solution consider implementing the property with OnPropertyChanged() like this:
int _example;
public int Example
{
get
{
return _example;
}
set
{
_example = value;
OnPropertyChanged(nameof(Example);
}
}
Your code will be less error prone.
Do it as easy as possible:
public class ViewModel : INotifyPropertyChanged
{
public ObservableCollection<string> Strings { get; set; }
public ICommand AddAnotherStringCommand { get; set; }
string _selectedItem;
public string SelectedItem
{
get
{
return _selectedItem;
}
set
{
_selectedItem = value;
OnPropertyChanged(nameof(this.SelectedItem));
}
}
public int counter { get; set; } = 1;
public ViewModel()
{
// RelayCommand from: https://stackoverflow.com/questions/22285866/why-relaycommand
this.AddAnotherStringCommand = new RelayCommand<object>(AddAnotherString);
this.Strings = new ObservableCollection<string>();
this.Strings.Add("First item");
}
private void AddAnotherString(object notUsed = null)
{
this.Strings.Add(counter.ToString());
counter++;
this.SelectedItem = counter.ToString();
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Main Window:
<Window x:Class="Test.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:Test"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:ViewModel x:Name="ViewModel" />
</Window.DataContext>
<StackPanel>
<ComboBox ItemsSource="{Binding Strings}" SelectedItem="{Binding SelectedItem}"/>
<Button Content="Add another item" Command="{Binding AddAnotherStringCommand}" />
</StackPanel>
</Window>
In my case the value is changed every time, but you should be able to modify the code to fit your needs.
Make sure that you have a clear code structure and do not overcomplicate things.
If you want a more specific answer you should consider to present you whole code.

PropertyChanged is null wpf

Help me please!!!
I have 3 UserControls
I select user on List Users UC listbox
Then send message from SendMessage UC to Database
when i send message to Db it must refresh my chat listBox in Correspondence UC, but problem is in my ChatWrapper.
PropertyChanged in ChatWrapper is always null, and I can't refresh my ListBox in Correspondence UC with new message
List Users:
public IEnumerable<EmployeesDb> getListNames
{
get { return Db.Instance.EmployeesDbs.ToList(); }
}
static EmployeesDb m_selectedUser;
public static EmployeesDb selectedUser
{
get { return m_selectedUser; }
set
{
if (value != null)
m_selectedUser = value;
Correspondence correspondence = new Correspondence();
correspondence.CorrespondenceChat();
}
}
}
Send Message ( I try to refresh -> SendInfo.FirstOrDefault().RefreshGUI();)
public static DependencyProperty SendInfoProperty =
DependencyProperty.Register(
"SendInfo",
typeof(IEnumerable<ChatWrapper>),
typeof(SendMessage));
public IEnumerable<ChatWrapper> SendInfo
{
get { return GetValue(SendInfoProperty) as IEnumerable<ChatWrapper>; }
set { SetValue(SendInfoProperty, value); }
}
void SendMessageCommandExecute()
{
//...
SendInfo.FirstOrDefault().RefreshGUI();
//...
}
ChatWrapper
public class ChatWrapper : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void FirePropertyChanged(string name)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(name));
}
public void RefreshGUI()
{
FirePropertyChanged("message");
}
public ChatDb chatDb { get; set; }
public string message
{
get
{
return (chatDb != null) ? string.Format("{0} {1}.{2} / {3} / {4}\n{5}",
chatDb.FromEmployeesDb.surname,
chatDb.FromEmployeesDb.name[0],
chatDb.FromEmployeesDb.middleName[0],
chatDb.messageDateTime,
chatDb.computerName,
chatDb.message) : null;
}
}
Correspondence
//...
public partial class Correspondence : UserControl, INotifyPropertyChanged
{
public static DependencyProperty GetCorrespondenceInfoProperty =
DependencyProperty.Register(
"GetCorrespondenceInfo",
typeof(IEnumerable<ChatWrapper>),
typeof(Correspondence),
new PropertyMetadata(OnChanged));
public IEnumerable<ChatWrapper> GetCorrespondenceInfo
{
get { return GetValue(GetCorrespondenceInfoProperty) as IEnumerable<ChatWrapper>; }
set { SetValue(GetCorrespondenceInfoProperty, value); }
}
static void OnChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var me = d as Correspondence;
me.chat = me.GetCorrespondenceInfo;
}
ICollectionView m_CollectionView;
public static IEnumerable<ChatWrapper> m_chat;
public IEnumerable<ChatWrapper> chat
{
get { return m_chat; }
set
{
m_chat = value;
if (ListUsers.selectedUser != null)
CorrespondenceChat();
FirePropertyChanged("chat");
}
}
public void CorrespondenceChat()
{
if (m_chat == null)
return;
m_CollectionView = CollectionViewSource.GetDefaultView(m_chat);
//...
FirePropertyChanged("chat");
}
XAML of Correspondence (refresh
<Grid>
<ListBox x:Name="correspondenceListBox" ItemsSource="{Binding chat, RelativeSource={RelativeSource AncestorType={x:Type local:Correspondence}}}"
Height="auto" Grid.Row="0" Grid.Column="1" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch" >
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding message}" TextWrapping="Wrap" Width="auto"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
I tried to write
public event PropertyChangedEventHandler PropertyChanged = delegate { };
PropertyChanged is no longer null, but it's still not updated

How to update datagrid xaml MVVM style

I am very new to this MVVM idea, was trying to write my first MVVM application to get my feet wet. Got a little bit of progress but hit road block as I progress. My question is a very basic fundamental one that could be easily addressed with code behind, but it was discouraged to do so as it violates the loose coupling principal I guess. So this is the problem I have:
My Model:
public class ToDoItemModel
{
private DateTime _TodoDate;
private string _TodoDescription;
private TimeSpan _TodoTimeSpan;
private string _StartTime;
public string StartTime
{
get { return _StartTime; }
set
{
_StartTime = value;
}
}
public TimeSpan ToDoTimeSpan
{
get { return _TodoTimeSpan; }
set
{
_TodoTimeSpan = value;
}
}
public string ToDoDescription
{
get { return _TodoDescription; }
set
{
_TodoDescription = value;
}
}
public DateTime ToDoDate
{
get { return _TodoDate; }
set
{
_TodoDate = value;
}
}
public override string ToString()
{
return string.Format("Date: {0}- Time: {1}- Duration: {2}- Description: {3}",_TodoDate.ToString("d"),_StartTime,_TodoTimeSpan,_TodoDescription);
}
}
My viewModel:
public class ToDoListModelView:INotifyPropertyChanged
{
List<ToDoItemModel> _myModel = new List<ToDoItemModel>();
public ICommand AddToDo
{
get
{
return new RelayCommand(addToDo);
}
}
public ToDoListModelView()
{
_myModel.Add(new ToDoItemModel() { ToDoDate = DateTime.Now, ToDoDescription = "Testing 1" });
_myModel.Add(new ToDoItemModel() { ToDoDate = DateTime.Now.AddDays(1), ToDoDescription = "Testing 2" });
}
public List<ToDoItemModel> myModel
{
get { return _myModel; }
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(PropertyChangedEventArgs e)
{
var handler = this.PropertyChanged;
if (handler!=null)
{
handler(this, e);
}
}
public void RaisePropertyChanged(string PropertyName)
{
OnPropertyChanged(new PropertyChangedEventArgs(PropertyName));
}
private void addToDo()
{
_myModel.Add(new ToDoItemModel() { ToDoDate = DateTime.Now.AddDays(2), ToDoDescription = "From Relay Command" });
RaisePropertyChanged("DataGridChanged");
}
}
The viewModel implements INotifyPropertyChanged, and use a class RelayCommand that implements ICommand interface.
My view is:
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestWPF" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" x:Class="TestWPF.MainWindow"
Title="MainWindow" Height="350" Width="525">
<Grid Margin="1,0,-1,0" d:DataContext="{d:DesignData /SampleData/ToDoListModelSampleData.xaml}">
<Button x:Name="AddToDoButton" Content="Add Todo Item
"
HorizontalAlignment="Left" Margin="419,90,0,0" VerticalAlignment="Top" Width="78" Height="33.04"
Command="{Binding AddToDo}"/>
<DataGrid x:Name="TodoList" HorizontalAlignment="Left"
Margin="33,184,0,0" VerticalAlignment="Top"
RenderTransformOrigin="-0.833,-0.846" Height="108" Width="464"
ItemsSource="{Binding myModel}"
Style="{DynamicResource ToDoEntry}"/>
</Grid>
</Window>
When I hit F5 the application ran and the 2 initial records were displayed.
However, when I hit the button add, I saw the new record was added internally but the datagrid was not updated. I know the datagrid needs to be refreshed somehow, but I am not sure how to tell the grid to refresh the way MVVM is supposed to handle.
My current code behind is as simple as that:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new ToDoListModelView();
}
}
According to the documentation I read from Microsoft site and if I understand it correctly, RaisePropertyChange is supposed to flag a change event occurs, I am just confused how to tie the event to refresh the grid using xaml without any code behind. Please help.

Change your List<ToDoItemModel> to an ObservableCollection<ToDoItemModel>
A List<T> does not notify the UI to update when an item gets added or removed from the collection, while an ObservableCollection<T> does.

You need to Use Binding Mode TwoWay also change your List to ObservableCollection
An ObservableCollection will notify the UI when a record is added or removed.
ObservableCollection<ToDoItemModel> _myModel = new ObservableCollection<ToDoItemModel>();
public ICommand AddToDo
{
get
{
return new RelayCommand(addToDo);
}
}
public ToDoListModelView()
{
_myModel.Add(new ToDoItemModel() { ToDoDate = DateTime.Now, ToDoDescription = "Testing 1" });
_myModel.Add(new ToDoItemModel() { ToDoDate = DateTime.Now.AddDays(1), ToDoDescription = "Testing 2" });
}
public ObservableCollection <ToDoItemModel> myModel
{
get { return _myModel; }
}
XAML:
<DataGrid x:Name="TodoList" HorizontalAlignment="Left"
Margin="33,184,0,0" VerticalAlignment="Top"
RenderTransformOrigin="-0.833,-0.846" Height="108" Width="464"
ItemsSource="{Binding myModel,Mode=TwoWay}"
Style="{DynamicResource ToDoEntry}"/>

Use ObservableCollection instead of Lists (as it was told above), and set
UpdateSourceTrigger=PropertyChanged in the XAML.
CODE:
<DataGrid x:Name="TodoList" HorizontalAlignment="Left"
Margin="33,184,0,0" VerticalAlignment="Top"
RenderTransformOrigin="-0.833,-0.846" Height="108" Width="464"
ItemsSource="{Binding Path=myModel,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged }"
Style="{DynamicResource ToDoEntry}"/>

WPF Newbie: updating textbox value

I bind a class which derived from INotifyPropertyChange to a Datacontext.
after some interaction, a value will be calculated and output property will be updated.
My problem is that the result textbox didn't update at all.
public partial class setraSubWpfTolerance : UserControl
{
public setraFit objSource = new setraFit();
public setraSubWpfTolerance()
{
InitializeComponent();
this.DataContext = objSource;
}
}
And the class:
public class setraFit : INotifyPropertyChanged
{
private readonly CollectionView _BoreSystems;
public CollectionView BoreSystems
{
get { return _BoreSystems; }
}
private decimal? _MaxBoreDimension;
public decimal? MaxBoreDimension
{
get { return _MaxBoreDimension; }
set
{
if (_MaxBoreDimension == value) return;
_MaxBoreDimension = value;
onPropertyChanged("MaxBoreDimension");
}
}
private string _BoreSystem;
public string BoreSystem
{
get { return _BoreSystem; }
set
{
if (_BoreSystem == value) return;
_BoreSystem = value;
calcBoreDimension();
onPropertyChanged("BoreSystem");
}
}
public setraFit()
{
IList<string> listBore = setraStaticTolerance.getBoreList();
_BoreSystems = new CollectionView(listBore);
}
public event PropertyChangedEventHandler PropertyChanged;
private void onPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
private void calcBoreDimension()
{
_MaxBoreDimension = (decimal)100.035;
}
}
Last but not least the XAML
<UserControl x:Class="SetraSubForms.setraSubWpfTolerance"
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"
d:DesignHeight="450" d:DesignWidth="375">
<Grid>
<ComboBox Height="23" HorizontalAlignment="Left" Margin="194,10,0,0" Name="BoreSystemComboBox" VerticalAlignment="Top" Width="120"
ItemsSource="{Binding Path=BoreSystems}"
SelectedValue="{Binding Path=BoreSystem}"/>
<TextBox HorizontalAlignment="Left" Margin="194,67,0,37" Name="MaxDimBoreTextBox" Width="120" IsReadOnly="False"
Text="{Binding Path=MaxBoreDimension, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"/>
</Grid>
</UserControl>
I expected to receive the dummy value of 100.035 after changing the combobox but the textbox did not update. If i run step by step i can see the "MaxBoreDimension" property of setraFit is changed.
What did i do wrong?
Thanks in advance for your help
sittingDuck

Your method is updating the private value, not the Property:
private void calcBoreDimension()
{
_MaxBoreDimension = (decimal)100.035;
}
Change to
private void calcBoreDimension()
{
MaxBoreDimension = (decimal)100.035;
}
You're doing the same thing in the constructor, which is causing your calcBoreDimension method to not run:
public setraFit()
{
IList<string> listBore = setraStaticTolerance.getBoreList();
_BoreSystems = new CollectionView(listBore);
}
should be
public setraFit()
{
IList<string> listBore = setraStaticTolerance.getBoreList();
BoreSystems = new CollectionView(listBore); //this line!
}
When you create properties that point to private fields, you should almost never have to set the private field anywhere other than the property. This is why properties exist- so that whenever you get or set them, you will run the code in the get and set blocks instead of just retrieving the current value.

SOLVED!
The key is to initate the PropertyChanged event for the "MaxBoreDimension"
public decimal? NominalDimension
{
get { return _NominalDimension; }
set
{
if (_NominalDimension == value) return;
_NominalDimension = value;
calcBoreDimension();
onPropertyChanged("NominalDimension");
onPropertyChanged("MaxBoreDimension");
}
}
Thanks DLeh for the contribution.

Binding multi listbox itemsouce with 1 ObserverableCollection of usercontrol

I have two listbox define below:
<ListBox x:Name="RemoteListBox" HorizontalAlignment="Right" Margin="0,88.5,8,0"
Width="382.5"
HorizontalContentAlignment="Stretch"
ItemsSource ="{Binding RemoteItemsList}"
SelectedIndex="0">
</ListBox>
<ListBox x:Name="LibraryListBox"
Margin="4.5,88.5,437,0"
HorizontalContentAlignment="Stretch"
ItemsSource="{Binding LibraryItemsList}"
SelectedIndex="0">
</ListBox>
My viewmodel
private ObservableCollection<MotionTitleItem> _remoteItemsList;
public ObservableCollection<MotionTitleItem> RemoteItemsList
{
get { return _remoteItemsList; }
set
{
_remoteItemsList = value;
NotifyPropertyChanged("RemoteItemsList");
}
}
private ObservableCollection<MotionTitleItem> _libraryItemsList
public ObservableCollection<MotionTitleItem> LibraryItemsList
{
get { return _libraryItemsList; }
set
{
_libraryItemsList = value;
NotifyPropertyChanged("LibraryItemsList");
}
}
I bind two ListBox ItemSource with a ObserverableCollection define below:
var listMotion = new ObservableCollection<MotionTitleItem>();
foreach (MotionInfo info in listMotionInfo)
{
var motionTitleItem = new MotionTitleItem();
listMotion.Add(motionTitleItem);
}
viewModel.RemoteItemsList = listMotion;
viewModel.LibraryItemsList = listMotion;
MotionTitleItem is a custom user control.
My problem is only the first ListBox with ItemSource binding with RemoteListItem displays the Item in UI, the other doest not.
If I bind two ListBox ItemSource with 2 ObserverableCollection, the problem solved:
var listMotion = new ObservableCollection<MotionTitleItem>();
var listMotion2 = new ObservableCollection<MotionTitleItem>();
foreach (MotionInfo info in listMotionInfo)
{
var motionTitleItem = new MotionTitleItem();
listMotion.Add(motionTitleItem);
var motionTitleItem2 = new MotionTitleItem();
listMotion2.Add(motionTitleItem2);
}
viewModel.RemoteItemsList = listMotion;
viewModel.LibraryItemsList = listMotion2;
Could someone explain to me where is the point of the first scenario problem?

I don't know why you used two temporary list for this. You can directly add items to your Observable collection. Try this :
foreach (MotionInfo info in listMotionInfo)
{
viewModel.RemoteItemsList.Add(info);
viewModel.LibraryItemsList.Add(info);
}
Below, I tried to create the solution for you.
I assumed the model MotionTitleItem.
public class MotionTitleItem
{
string _name = string.Empty;
public string Name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged("Name");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
try
{
PropertyChangedEventHandler eventHandler = this.PropertyChanged;
if (null == eventHandler)
return;
else
{
var e = new PropertyChangedEventArgs(propertyName);
eventHandler(this, e);
}
}
catch (Exception)
{
throw;
}
}
}
My view model for this application is:
public class MotionTitleItemViewModel : INotifyPropertyChanged
{
ObservableCollection<MotionTitleItem> _remoteItemsList = new ObservableCollection<MotionTitleItem>();
public ObservableCollection<MotionTitleItem> RemoteItemsList
{
get { return _remoteItemsList; }
set { _remoteItemsList = value; }
}
ObservableCollection<MotionTitleItem> _libraryItemsList = new ObservableCollection<MotionTitleItem>();
public ObservableCollection<MotionTitleItem> LibraryItemsList
{
get { return _libraryItemsList; }
set { _libraryItemsList = value; }
}
public MotionTitleItemViewModel()
{
MotionTitleItem motion;
for (int i = 0; i < 10; i++)
{
motion = new MotionTitleItem();
motion.Name = "Name " + i.ToString();
this.LibraryItemsList.Add(motion);
this.RemoteItemsList.Add(motion);
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
try
{
PropertyChangedEventHandler eventHandler = this.PropertyChanged;
if (null == eventHandler)
return;
else
{
var e = new PropertyChangedEventArgs(propertyName);
eventHandler(this, e);
}
}
catch (Exception)
{
throw;
}
} }
My View is :
<Window x:Class="WPFExperiments.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ListBox x:Name="RemoteListBox" HorizontalAlignment="Right" Margin="0,0.5,8,0"
Width="382.5"
HorizontalContentAlignment="Stretch"
ItemsSource ="{Binding RemoteItemsList}"
SelectedIndex="0">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<ListBox x:Name="LibraryListBox"
Margin="4.5,0.5,437,0"
HorizontalContentAlignment="Stretch"
ItemsSource="{Binding LibraryItemsList}"
SelectedIndex="0">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Window>
In code behind of this window i set DataContext to view model.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new MotionTitleItemViewModel();
}}
This code is working for me.
Here is screenshot of the output.
Vote this answer if you find it useful.
Have fun!

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