Dan Walmsley
4 years ago
committed by
GitHub
GitHub
25 changed files with 663 additions and 314 deletions
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<ProjectConfiguration> |
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<Settings> |
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<IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely> |
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</Settings> |
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</ProjectConfiguration> |
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@ -0,0 +1,5 @@ |
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<ProjectConfiguration> |
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<Settings> |
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<IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely> |
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</Settings> |
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</ProjectConfiguration> |
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@ -0,0 +1,165 @@ |
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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.Diagnostics.CodeAnalysis; |
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using Avalonia.Collections; |
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namespace Avalonia.Controls |
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{ |
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/// <summary>
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/// Holds the list of items that constitute the content of an <see cref="ItemsControl"/>.
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/// </summary>
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public class ItemCollection : ItemsSourceView, IList |
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{ |
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// Suppress "Avoid zero-length array allocations": This is a sentinel value and must be unique.
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#pragma warning disable CA1825
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private static readonly object?[] s_uninitialized = new object?[0]; |
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#pragma warning restore CA1825
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private Mode _mode; |
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internal ItemCollection() |
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: base(s_uninitialized) |
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{ |
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} |
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public new object? this[int index] |
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{ |
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get => base[index]; |
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set => WritableSource[index] = value; |
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} |
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public bool IsReadOnly => _mode == Mode.ItemsSource; |
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internal event EventHandler? SourceChanged; |
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/// <summary>
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/// Adds an item to the <see cref="ItemsControl"/>.
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/// </summary>
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/// <param name="value">The item to add to the collection.</param>
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/// <returns>
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/// The position into which the new element was inserted, or -1 to indicate that
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/// the item was not inserted into the collection.
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/// </returns>
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/// <exception cref="InvalidOperationException">
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/// The collection is in ItemsSource mode.
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/// </exception>
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public int Add(object? value) => WritableSource.Add(value); |
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/// <summary>
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/// Clears the collection and releases the references on all items currently in the
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/// collection.
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/// </summary>
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/// <exception cref="InvalidOperationException">
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/// The collection is in ItemsSource mode.
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/// </exception>
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public void Clear() => WritableSource.Clear(); |
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/// <summary>
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/// Inserts an element into the collection at the specified index.
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/// </summary>
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/// <param name="index">The zero-based index at which to insert the item.</param>
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/// <param name="value">The item to insert.</param>
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/// <exception cref="InvalidOperationException">
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/// The collection is in ItemsSource mode.
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/// </exception>
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public void Insert(int index, object? value) => WritableSource.Insert(index, value); |
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/// <summary>
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/// Removes the item at the specified index of the collection or view.
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/// </summary>
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/// <param name="index">The zero-based index of the item to remove.</param>
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/// <exception cref="InvalidOperationException">
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/// The collection is in ItemsSource mode.
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/// </exception>
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public void RemoveAt(int index) => WritableSource.RemoveAt(index); |
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/// <summary>
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/// Removes the specified item reference from the collection or view.
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/// </summary>
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/// <param name="value">The object to remove.</param>
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/// <returns>True if the item was removed; otherwise false.</returns>
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/// <exception cref="InvalidOperationException">
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/// The collection is in ItemsSource mode.
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/// </exception>
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public bool Remove(object? value) |
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{ |
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var c = Count; |
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WritableSource.Remove(value); |
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return Count < c; |
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} |
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int IList.Add(object? value) => Add(value); |
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void IList.Clear() => Clear(); |
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void IList.Insert(int index, object? value) => Insert(index, value); |
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void IList.RemoveAt(int index) => RemoveAt(index); |
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private IList WritableSource |
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{ |
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get |
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{ |
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if (IsReadOnly) |
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ThrowIsItemsSource(); |
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if (Source == s_uninitialized) |
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SetSource(CreateDefaultCollection()); |
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return Source; |
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} |
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} |
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internal IList? GetItemsPropertyValue() |
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{ |
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if (_mode == Mode.ObsoleteItemsSetter) |
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return Source == s_uninitialized ? null : Source; |
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return this; |
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} |
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internal void SetItems(IList? items) |
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{ |
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_mode = Mode.ObsoleteItemsSetter; |
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SetSource(items ?? s_uninitialized); |
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} |
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internal void SetItemsSource(IEnumerable? value) |
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{ |
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if (_mode != Mode.ItemsSource && Count > 0) |
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throw new InvalidOperationException( |
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"Items collection must be empty before using ItemsSource."); |
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_mode = value is not null ? Mode.ItemsSource : Mode.Items; |
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SetSource(value ?? CreateDefaultCollection()); |
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} |
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private new void SetSource(IEnumerable source) |
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{ |
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var oldSource = Source; |
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base.SetSource(source); |
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if (oldSource.Count > 0) |
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RaiseCollectionChanged(new(NotifyCollectionChangedAction.Remove, oldSource, 0)); |
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if (Source.Count > 0) |
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RaiseCollectionChanged(new(NotifyCollectionChangedAction.Add, Source, 0)); |
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SourceChanged?.Invoke(this, EventArgs.Empty); |
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} |
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private static AvaloniaList<object?> CreateDefaultCollection() |
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{ |
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return new() { ResetBehavior = ResetBehavior.Remove }; |
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} |
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[DoesNotReturn] |
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private static void ThrowIsItemsSource() |
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{ |
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throw new InvalidOperationException( |
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"Operation is not valid while ItemsSource is in use." + |
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"Access and modify elements with ItemsControl.ItemsSource instead."); |
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} |
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private enum Mode |
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{ |
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Items, |
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ItemsSource, |
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ObsoleteItemsSetter, |
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} |
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} |
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} |
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