Steven Kirk
6 years ago
9 changed files with 819 additions and 745 deletions
File diff suppressed because it is too large
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using System; |
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using System.Collections; |
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using System.Collections.Specialized; |
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using System.ComponentModel; |
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using System.Linq; |
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using Avalonia.Collections; |
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using Avalonia.Controls.Selection; |
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#nullable enable |
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namespace Avalonia.Controls.Utils |
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{ |
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/// <summary>
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/// Synchronizes an <see cref="ISelectionModel"/> with a list of SelectedItems.
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/// </summary>
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internal class SelectedItemsSync |
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{ |
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private IList? _selectedItems; |
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private bool _updatingItems; |
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private bool _updatingModel; |
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private bool _initializeOnSourceAssignment; |
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public SelectedItemsSync(ISelectionModel model) |
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{ |
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model = model ?? throw new ArgumentNullException(nameof(model)); |
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Model = model; |
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} |
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public ISelectionModel Model { get; private set; } |
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public IList GetOrCreateSelectedItems() |
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{ |
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if (_selectedItems == null) |
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{ |
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var items = new AvaloniaList<object?>(Model.SelectedItems); |
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items.CollectionChanged += ItemsCollectionChanged; |
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Model.SelectionChanged += SelectionModelSelectionChanged; |
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_selectedItems = items; |
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} |
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return _selectedItems; |
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} |
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public void SetSelectedItems(IList? items) |
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{ |
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items ??= new AvaloniaList<object>(); |
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if (items.IsFixedSize) |
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{ |
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throw new NotSupportedException( |
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"Cannot assign fixed size selection to SelectedItems."); |
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} |
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if (_selectedItems is INotifyCollectionChanged incc) |
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{ |
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incc.CollectionChanged -= ItemsCollectionChanged; |
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} |
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if (_selectedItems == null) |
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{ |
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Model.SelectionChanged += SelectionModelSelectionChanged; |
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} |
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try |
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{ |
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_updatingModel = true; |
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_selectedItems = items; |
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if (Model.Source is object) |
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{ |
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using (Model.BatchUpdate()) |
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{ |
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Model.Clear(); |
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Add(items); |
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} |
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} |
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else if (!_initializeOnSourceAssignment) |
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{ |
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Model.PropertyChanged += SelectionModelPropertyChanged; |
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_initializeOnSourceAssignment = true; |
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} |
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if (_selectedItems is INotifyCollectionChanged incc2) |
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{ |
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incc2.CollectionChanged += ItemsCollectionChanged; |
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} |
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} |
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finally |
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{ |
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_updatingModel = false; |
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} |
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} |
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public void SetModel(ISelectionModel model) |
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{ |
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model = model ?? throw new ArgumentNullException(nameof(model)); |
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if (_selectedItems != null) |
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{ |
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Model.PropertyChanged -= SelectionModelPropertyChanged; |
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Model.SelectionChanged -= SelectionModelSelectionChanged; |
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Model = model; |
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Model.SelectionChanged += SelectionModelSelectionChanged; |
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_initializeOnSourceAssignment = false; |
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try |
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{ |
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_updatingItems = true; |
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_selectedItems.Clear(); |
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foreach (var i in model.SelectedItems) |
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{ |
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_selectedItems.Add(i); |
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} |
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} |
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finally |
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{ |
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_updatingItems = false; |
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} |
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} |
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} |
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private void ItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) |
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{ |
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if (_updatingItems) |
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{ |
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return; |
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} |
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if (_selectedItems == null) |
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{ |
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throw new AvaloniaInternalException("CollectionChanged raised but we don't have items."); |
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} |
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void Remove() |
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{ |
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foreach (var i in e.OldItems) |
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{ |
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var index = IndexOf(Model.Source, i); |
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if (index != -1) |
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{ |
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Model.Deselect(index); |
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} |
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} |
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} |
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try |
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{ |
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using var operation = Model.BatchUpdate(); |
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_updatingModel = true; |
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switch (e.Action) |
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{ |
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case NotifyCollectionChangedAction.Add: |
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Add(e.NewItems); |
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break; |
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case NotifyCollectionChangedAction.Remove: |
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Remove(); |
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break; |
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case NotifyCollectionChangedAction.Replace: |
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Remove(); |
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Add(e.NewItems); |
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break; |
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case NotifyCollectionChangedAction.Reset: |
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Model.Clear(); |
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Add(_selectedItems); |
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break; |
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} |
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} |
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finally |
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{ |
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_updatingModel = false; |
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} |
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} |
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private void Add(IList newItems) |
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{ |
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foreach (var i in newItems) |
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{ |
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var index = IndexOf(Model.Source, i); |
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if (index != -1) |
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{ |
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Model.Select(index); |
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} |
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} |
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} |
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private void SelectionModelPropertyChanged(object sender, PropertyChangedEventArgs e) |
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{ |
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if (_initializeOnSourceAssignment && |
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_selectedItems != null && |
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e.PropertyName == nameof(ISelectionModel.Source)) |
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{ |
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try |
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{ |
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_updatingModel = true; |
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Add(_selectedItems); |
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_initializeOnSourceAssignment = false; |
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} |
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finally |
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{ |
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_updatingModel = false; |
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} |
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} |
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} |
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private void SelectionModelSelectionChanged(object sender, SelectionModelSelectionChangedEventArgs e) |
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{ |
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if (_updatingModel) |
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{ |
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return; |
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} |
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if (_selectedItems == null) |
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{ |
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throw new AvaloniaInternalException("SelectionModelChanged raised but we don't have items."); |
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} |
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try |
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{ |
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var deselected = e.DeselectedItems.ToList(); |
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var selected = e.SelectedItems.ToList(); |
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_updatingItems = true; |
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foreach (var i in deselected) |
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{ |
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_selectedItems.Remove(i); |
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} |
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foreach (var i in selected) |
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{ |
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_selectedItems.Add(i); |
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} |
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} |
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finally |
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{ |
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_updatingItems = false; |
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} |
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} |
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private static int IndexOf(object? source, object? item) |
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{ |
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if (source is IList l) |
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{ |
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return l.IndexOf(item); |
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} |
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else if (source is ItemsSourceView v) |
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{ |
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return v.IndexOf(item); |
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} |
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return -1; |
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} |
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} |
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} |
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