108 lines
3.9 KiB
C#
108 lines
3.9 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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using System.IO;
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using System.Reflection;
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namespace Nuclex.Support.Collections {
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/// <summary>Collection that automatically assigns an owner to all its elements</summary>
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/// <remarks>
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/// This collection automatically assigns a parent object to elements that
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/// are managed in it. The elements have to derive from the Parentable<>
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/// base class.
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/// </remarks>
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/// <typeparam name="ParentType">Type of the parent object to assign to items</typeparam>
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/// <typeparam name="ItemType">Type of the items being managed in the collection</typeparam>
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public class ParentingCollection<ParentType, ItemType> : Collection<ItemType>, IDisposable
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where ItemType : Parentable<ParentType>
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where ParentType : class {
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/// <summary>Called when the object is garbage-collected</summary>
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~ParentingCollection() {
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Dispose(false); // called from GC
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}
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/// <summary>Reparents all elements in the collection</summary>
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/// <param name="parent">New parent to take ownership of the items</param>
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internal void Reparent(ParentType parent) {
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this.parent = parent;
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for(int index = 0; index < Count; ++index)
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base[index].SetParent(parent);
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}
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/// <summary>Called when the asset needs to release its resources</summary>
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/// <param name="calledByUser">
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/// Whether the mehod has been called from user code. If this argument
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/// is false, the object is being disposed by the garbage collection and
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/// it mustn't access other objects (including the attempt to Dispose() them)
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/// as these might have already been destroyed by the GC.
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/// </param>
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protected virtual void Dispose(bool calledByUser) {
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// Only destroy the other resources when we're not being called from
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// the garbage collector, otherwise we'd risk accessing objects that
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// have already been disposed
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if(calledByUser) {
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// Have the items do their cleanup work
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Reparent(null);
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// Dispose of all the items in the collection
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foreach(ItemType item in this) {
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IDisposable disposable = item as IDisposable;
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if(disposable != null)
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disposable.Dispose();
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}
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// Remove all items from the collection
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base.ClearItems();
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}
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}
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/// <summary>Clears all elements from the collection</summary>
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protected override void ClearItems() {
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for(int index = 0; index < Count; ++index)
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base[index].SetParent(null);
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base.ClearItems();
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}
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/// <summary>Inserts a new element into the collection</summary>
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/// <param name="index">Index at which to insert the element</param>
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/// <param name="item">Item to be inserted</param>
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protected override void InsertItem(int index, ItemType item) {
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base.InsertItem(index, item);
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item.SetParent(this.parent);
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}
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/// <summary>Removes an element from the collection</summary>
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/// <param name="index">Index of the element to remove</param>
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protected override void RemoveItem(int index) {
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base[index].SetParent(null);
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base.RemoveItem(index);
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}
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/// <summary>Takes over a new element that is directly assigned</summary>
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/// <param name="index">Index of the element that was assigned</param>
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/// <param name="item">New item</param>
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protected override void SetItem(int index, ItemType item) {
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base.SetItem(index, item);
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item.SetParent(this.parent);
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}
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/// <summary>Release all resources owned by the instance explicitely</summary>
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void IDisposable.Dispose() {
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Dispose(true); // Called by user
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}
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/// <summary>Parent this collection currently belongs to</summary>
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private ParentType parent;
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}
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} // namespace Nuclex.Support.Collections
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