two usercontrols with different dependency properties have the same content

Question

i have a usercontrol called filtercontrol that's in a in a itemscontrol. the itemscontrol ist bound to a observablecollection. the usercontrol has a dependency property that's set a guid. wenn the guid is set the usercontrol gets data from a source to fill itself.

when i run the program the usercontrols have different guid's that's returns different data but both of them display the data of the last.

xaml itemscontrol

xaml filtercontrol

codebehind filtercontrol

using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
 
namespace MailFilter.WPF
{
    /// 
    /// Interaktionslogik für FilterControl.xaml
    /// 
    public partial class FilterControl : UserControl
    {
        private static readonly ObservableCollection _rules = [];
        private static readonly ObservableCollection _actions = [];
        private static readonly Core.MailFilter mailFilter = MainWindow.Instance.MailFilter;
        public static readonly DependencyProperty guid = DependencyProperty
            .Register("Guid",
            typeof(string),
            typeof(FilterControl),
            new PropertyMetadata(default(string), new PropertyChangedCallback(UpdateControl)));
 
        public string Guid
        {
            get => (string)GetValue(guid);
            set => SetValue(guid, value);
        }
 
        public FilterControl()
        {
            InitializeComponent();
            RulesPanel.ItemsSource = _rules;
            ActionsPanel.ItemsSource = _actions;
        }
 
        private static void UpdateControl(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            IEnumerable rules = from filter in mailFilter.Filters
                                            where filter.Guid == e.NewValue.ToString()
                                            from rule in filter.Rules
                                            select rule;
 
            IEnumerable actions = from filter in mailFilter.Filters
                                                where filter.Guid == e.NewValue.ToString()
                                                from action in filter.Actions
                                                select action;
 
            _rules.Clear();
            _actions.Clear();
 
            foreach (FilterRule rule in rules)
            {
                _rules.Add(RepresenterConverter.ConvertToRepresenter(rule));
            }
 
            foreach (FilterAction action in actions)
            {
                _actions.Add(RepresenterConverter.ConvertToRepresenter(action));
            }
        }
 
        private void BtnDeleteRule_Click(object sender, RoutedEventArgs e)
        {
            if (MessageBox.Show("Bedingung wirklich löschen?", "MailFilter", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
            {
                Button button = (sender as Button)!;
                RuleRepresenter ruleRepresenter = (from rule in _rules
                                                   where rule.Guid == button.Tag.ToString()
                                                   select rule).First();
 
                _rules.RemoveAt(_rules.IndexOf(ruleRepresenter));
                MainWindow.Instance.MailFilter.RemoveRule(ruleRepresenter.Guid);
            }
        }
 
        private void BtnDeleteAction_Click(object sender, RoutedEventArgs e)
        {
            if (MessageBox.Show("Aktion wirklich löschen?", "MailFilter", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
            {
                Button button = (sender as Button)!;
                ActionRepresenter actionRepresenter = (from action in _actions
                                                       where action.Guid == button.Tag.ToString()
                                                       select action).First();
 
                _actions.RemoveAt(_actions.IndexOf(actionRepresenter));
                MainWindow.Instance.MailFilter.RemoveAction(actionRepresenter.Guid);
            }
        }
 
        private void BtnRuleDataContextPopOut_Click(object sender, RoutedEventArgs e) =>
            new RuleDataContextPopOutWindow(
            (from rule in _rules
             where rule.Guid == (sender as Button)!.Tag.ToString()
             select rule.DataContext).First())
            .Show();
 
        private void Grid_Loaded(object sender, RoutedEventArgs e)
        {
            Grid grid = (sender as Grid)!;
 
            if ((from rule in _rules where rule.Guid == grid.Tag.ToString() select rule.RuleType).First() == 1)
            {
                (from object stackPanel in grid.Children
                 where stackPanel is StackPanel
                 from Button button in (stackPanel as StackPanel)!.Children
                 where button is Button && button.Name == "BtnRuleDataContextPopOut"
                 select button).First().Visibility = Visibility.Visible;
            }
        }
 
        private void TextBlock_Loaded(object sender, RoutedEventArgs e)
        {
            TextBlock textBlock = (sender as TextBlock)!;
            if (textBlock.Text == "O
R")
            {
                textBlock.Margin = new Thickness(-3, -3, 0, 0);
            }
        }
    }
}

Accepted Answer

Hi, @Jungbluth. Welcome to Microsoft Q&A.

Reason

The callback function UpdateControl that you registered for the dependency property Guid will run during the initial assignment. Assuming that your first ItemsControl (x:Name="FiltersPanel") has two values initially assigned, UpdateControl will run twice. Since UpdateControl contains _rules.Clear(); _actions.Clear(); and _rules and _actions are static properties, they will only display the last one and both display the same data.

Solution

1.Do not use static modified _rules and _actions to bind data, static will share the data to be bound. You could update data directly on RulesPanel and ActionsPanel. Reference code:

public FilterControl()
{
    InitializeComponent();
    //Do not use _rules and _actions for binding
    //RulesPanel.ItemsSource = _rules;
    //ActionsPanel.ItemsSource = _actions;
}

private static void UpdateControl(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    //Get RulesPanel and ActionsPanel
    var grid = (d as FilterControl).Content as Grid;
    var rulesPanel = grid.Children.OfType().Where(p=> "RulesPanel".Equals(p.Name)).FirstOrDefault();
    var actionsPanel = grid.Children.OfType().Where(p => "ActionsPanel".Equals(p.Name)).FirstOrDefault();

    IEnumerable rules = from filter in mailFilter.Filters
                                    where filter.Guid == e.NewValue.ToString()
                                    from rule in filter.Rules
                                    select rule;

    IEnumerable actions = from filter in mailFilter.Filters
                                        where filter.Guid == e.NewValue.ToString()
                                        from action in filter.Actions
                                        select action;

    //Update data directly on RulesPanel and ActionsPanel
    rulesPanel.Items.Clear();
    actionsPanel.Items.Clear();


    foreach (FilterRule rule in rules)
    {
        rulesPanel.Items.Add(RepresenterConverter.ConvertToRepresenter(rule));
    }

    foreach (FilterAction action in actions)
    {
        actionsPanel.Items.Add(RepresenterConverter.ConvertToRepresenter(action));
    }

    rulesPanel.Items.Refresh();
    actionsPanel.Items.Refresh();
}

2Make sure that the data stored in mailFilter should be separated from the data bound to FiltersPanel.ItemsSource.

3.At this time, the result of the Linq query may be empty, please change First to FirstOrDefault, for example:

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two usercontrols with different dependency properties have the same content

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