WPF ComboBox不会在propertychanged事件上更新

Question

I have a custom combobox in my WPF application and the combo box is not updating when my item source is updated after initial launch. The itemsSource is a custom observableDictionary. I've implemented INotifyPropertyChanged on my properties with my observableDictionary but it won't update. I've searched through every WPF propertychanged event not working on stack overflow and i'm looking for some assistance.

Custom Combobox Code:

<controls:MultiSelectComboBox Width="100" Height="30" Padding="0 10 0 0" Grid.Row="0" Grid.Column="1"
    ItemsSource="{Binding Mode=TwoWay,             
                  UpdateSourceTrigger=PropertyChanged,                                                    
                  ValidatesOnDataErrors=True, 
                  Path=DataContext.OptionTeamMembersDictionary, 
                  BindsDirectlyToSource=True,                                                    
                  RelativeSource={RelativeSource AncestorType={x:Type UserControl},Mode=FindAncestor}}"
    SelectedItems="{Binding SelectedOptionTeamMembersDictionary, Mode=TwoWay}"
    x:Name="TeamMemberDisplay" 
    ToolTip="{Binding Path=Text, RelativeSource={RelativeSource Self}}"/>

Properties and private variables:

private ObservableDictionary<string, object> _optionTeamMembersDictionary;
private ObservableDictionary<string, object> _selectedOptionTeamMembersDictionary;


public ObservableDictionary<string, object> OptionTeamMembersDictionary
{
    get
    {
        return _optionTeamMembersDictionary;
    }
    set
    {
        _optionTeamMembersDictionary = value;
        OnPropertyChanged("OptionTeamMembersDictionary");
    }
}

public ObservableDictionary<string, object> SelectedOptionTeamMembersDictionary
{
    get
    {
        return _selectedOptionTeamMembersDictionary;
    }
    set
    {
        _selectedOptionTeamMembersDictionary = value;
        OnPropertyChanged("SelectedOptionTeamMembersDictionary");
    }
}

I use a button to trigger a database pull which leads each row into an object and then populates the optionTeamMemberDictionary when it returns more then one row of data.

All of the above works when the data is loaded in my constructor but when its loaded after launch my comboboxes do not show the new data in the collection.

EDIT: Code for the Custom ComboBox being used: https://www.codeproject.com/Articles/563862/Multi-Select-ComboBox-in-WPF is the URL this came from. Some edits were made to implement an obserableDirctionary instead of normal dictionary

public partial class MultiSelectComboBox : UserControl
{
    private ObservableCollection<Node> _nodeList;
    public MultiSelectComboBox()
    {
        InitializeComponent();
        _nodeList = new ObservableCollection<Node>();
    }

    #region Dependency Properties

    public static readonly DependencyProperty ItemsSourceProperty =
         DependencyProperty.Register("ItemsSource", typeof(ObservableDictionary<string, object>), typeof(MultiSelectComboBox), new FrameworkPropertyMetadata(null,
    new PropertyChangedCallback(MultiSelectComboBox.OnItemsSourceChanged)));

    public static readonly DependencyProperty SelectedItemsProperty =
     DependencyProperty.Register("SelectedItems", typeof(ObservableDictionary<string, object>), typeof(MultiSelectComboBox), new FrameworkPropertyMetadata(null,
 new PropertyChangedCallback(MultiSelectComboBox.OnSelectedItemsChanged)));

    public static readonly DependencyProperty TextProperty =
       DependencyProperty.Register("Text", typeof(string), typeof(MultiSelectComboBox), new UIPropertyMetadata(string.Empty));

    public static readonly DependencyProperty DefaultTextProperty =
        DependencyProperty.Register("DefaultText", typeof(string), typeof(MultiSelectComboBox), new UIPropertyMetadata(string.Empty));

    public ObservableDictionary<string, object> ItemsSource
    {
        get { return (ObservableDictionary<string, object>)GetValue(ItemsSourceProperty); }
        set
        {
            SetValue(ItemsSourceProperty, value);
        }
    }

    public ObservableDictionary<string, object> SelectedItems
    {
        get { return (ObservableDictionary<string, object>)GetValue(SelectedItemsProperty); }
        set
        {
            SetValue(SelectedItemsProperty, value);
        }
    }

    public string Text
    {
        get { return (string)GetValue(TextProperty); }
        set { SetValue(TextProperty, value); }
    }

    public string DefaultText
    {
        get { return (string)GetValue(DefaultTextProperty); }
        set { SetValue(DefaultTextProperty, value); }
    }
    #endregion

    #region Events
    private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        MultiSelectComboBox control = (MultiSelectComboBox)d;
        control.DisplayInControl();
    }

    private static void OnSelectedItemsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        MultiSelectComboBox control = (MultiSelectComboBox)d;
        control.SelectNodes();
        control.SetText();
    }

    private void CheckBox_Click(object sender, RoutedEventArgs e)
    {
        CheckBox clickedBox = (CheckBox)sender;

        if (clickedBox.Content == "All")
        {
            if (clickedBox.IsChecked.Value)
            {
                foreach (Node node in _nodeList)
                {
                    node.IsSelected = true;
                }
            }
            else
            {
                foreach (Node node in _nodeList)
                {
                    node.IsSelected = false;
                }
            }
        }
        else
        {
            int _selectedCount = 0;
            foreach (Node s in _nodeList)
            {
                if (s.IsSelected && s.Title != "All")
                    _selectedCount++;
            }
            if (_selectedCount == _nodeList.Count - 1)
                _nodeList.FirstOrDefault(i => i.Title == "All").IsSelected = true;
            else
                _nodeList.FirstOrDefault(i => i.Title == "All").IsSelected = false;
        }
        SetSelectedItems();
        SetText();
    }
    #endregion

    #region Methods
    private void SelectNodes()
    {
        foreach (KeyValuePair<string, object> keyValue in SelectedItems)
        {
            Node node = _nodeList.FirstOrDefault(i => i.Title == keyValue.Key);
            if (node != null)
                node.IsSelected = true;
        }
    }

    private void SetSelectedItems()
    {
        if (SelectedItems == null)
            SelectedItems = new ObservableDictionary<string, object>();
        SelectedItems.Clear();
        foreach (Node node in _nodeList)
        {
            if (node.IsSelected && node.Title != "All")
            {
                if (this.ItemsSource.Count > 0)
                    SelectedItems.Add(node.Title, this.ItemsSource[node.Title]);
            }
        }
    }

    private void DisplayInControl()
    {
        _nodeList.Clear();
        if (this.ItemsSource.Count > 0)
            _nodeList.Add(new Node("All"));
        foreach (KeyValuePair<string, object> keyValue in this.ItemsSource)
        {
            Node node = new Node(keyValue.Key);
            _nodeList.Add(node);
        }
        MultiSelectCombo.ItemsSource = _nodeList;
    }

    private void SetText()
    {
        if (this.SelectedItems != null)
        {
            StringBuilder displayText = new StringBuilder();
            foreach (Node s in _nodeList)
            {
                if (s.IsSelected == true && s.Title == "All")
                {
                    displayText = new StringBuilder();
                    displayText.Append("All");
                    break;
                }
                else if (s.IsSelected == true && s.Title != "All")
                {
                    displayText.Append(s.Title);
                    displayText.Append(',');
                }
            }
            this.Text = displayText.ToString().TrimEnd(new char[] { ',' });
        }
        // set DefaultText if nothing else selected
        if (string.IsNullOrEmpty(this.Text))
        {
            this.Text = this.DefaultText;
        }
    }


    #endregion
}

public class Node : INotifyPropertyChanged
{

    private string _title;
    private bool _isSelected;
    #region ctor
    public Node(string title)
    {
        Title = title;
    }
    #endregion

    #region Properties
    public string Title
    {
        get
        {
            return _title;
        }
        set
        {
            _title = value;
            NotifyPropertyChanged("Title");
        }
    }
    public bool IsSelected
    {
        get
        {
            return _isSelected;
        }
        set
        {
            _isSelected = value;
            NotifyPropertyChanged("IsSelected");
        }
    }
    #endregion

    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

Answer 1

After much troubleshooting i was able to figure out an answer for this. onItemsSourceChanged was not firing after the control was instantiated so it never got updates made after initial launch of the application. I edited the OnItemsSourceChanged Function on the MultiFunctionComboBox to the below so it would fire on a changed event and it is working as expected now.

private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            MultiSelectComboBox control = (MultiSelectComboBox)d;

            var action = new NotifyCollectionChangedEventHandler(
                (o, args) =>
                {
                    MultiSelectComboBox c = (MultiSelectComboBox)d;

                    c?.DisplayInControl();
                });

            if (e.OldValue != null)
            {
                var sourceCollection = (ObservableDictionary<string, object>)e.OldValue;
                sourceCollection.CollectionChanged -= action;
            }

            if (e.NewValue != null)
            {
                var sourceCollection = (ObservableDictionary<string, object>)e.NewValue;
                sourceCollection.CollectionChanged += action;
            }

            control.DisplayInControl();
        }