Support copying elements from list to array with compatible types.

Author: hamster620

Core/Collections/FilteredObservableList.cs

@@ -339,7 +339,23 @@ void Rebuild()
         void IList.Clear() => throw new InvalidOperationException();
         void ICollection<T>.Clear() => throw new InvalidOperationException();
         bool IList.Contains(object? value) => value is T item && this.Contains(item);
-        void ICollection.CopyTo(System.Array array, int index) => this.CopyTo((T[])array, index);
+        void ICollection.CopyTo(System.Array array, int index)
+        {
+            if (array is T[] targetArray)
+				this.CopyTo(targetArray, index);
+            else if (array.GetType().GetElementType()!.IsAssignableFrom(typeof(T)))
+			{
+				var count = this.items.Count;
+				if (count == 0)
+					return;
+				if (index < 0 || (index + count) > array.Length)
+					throw new ArgumentOutOfRangeException(nameof(index));
+				for (var i = 0; i < count; ++i)
+					array.SetValue(this.items[i].Item1, index++);
+			}
+			else
+				throw new ArgumentException($"Type of array element {array.GetType().GetElementType()!.Name} is not parent type of {typeof(T).Name}.");
+        }
         IEnumerator IEnumerable.GetEnumerator() => this.GetEnumerator();
         int IList.IndexOf(object? value) => value is T item ? this.IndexOf(item) : -1;
         void IList.Insert(int index, object? value) => throw new InvalidOperationException();

Core/Collections/ObservableList.cs

@@ -376,7 +376,13 @@ static IList ToIList(IEnumerable<T> elements)
 
 		// Interface implementations.
 		void ICollection<T>.Add(T value) => this.Add(value);
-		void ICollection.CopyTo(Array array, int index) => this.CopyTo((T[])array, index);
+		void ICollection.CopyTo(Array array, int index)
+		{
+			if (array is T[] targetArray)
+				this.list.CopyTo(targetArray, index);
+			else
+				((ICollection)this.list).CopyTo(array, index);
+		}
 		bool ICollection<T>.IsReadOnly => false;
 		bool ICollection.IsSynchronized => false;
 		object ICollection.SyncRoot => this;

Core/Collections/ReadOnlyObservableList.cs

@@ -93,7 +93,25 @@ public ReadOnlyObservableList(IList<T> source)
 		// Interface implementations.
 		void ICollection<T>.Add(T value) => throw new InvalidOperationException();
 		void ICollection<T>.Clear() => throw new InvalidOperationException();
-		void ICollection.CopyTo(Array array, int index) => this.CopyTo((T[])array, index);
+		void ICollection.CopyTo(Array array, int index)
+		{
+			if (array is T[] targetArray)
+				this.sourceList.CopyTo(targetArray, index);
+			else if (this.sourceList is ICollection collection)
+				collection.CopyTo(array, index);
+			else if (array.GetType().GetElementType()!.IsAssignableFrom(typeof(T)))
+			{
+				var count = this.sourceList.Count;
+				if (count == 0)
+					return;
+				if (index < 0 || (index + count) > array.Length)
+					throw new ArgumentOutOfRangeException(nameof(index));
+				for (var i = 0; i < count; ++i)
+					array.SetValue(this.sourceList[i], index++);
+			}
+			else
+				throw new ArgumentException($"Type of array element {array.GetType().GetElementType()!.Name} is not parent type of {typeof(T).Name}.");
+		}
 		bool ICollection<T>.IsReadOnly => true;
 		bool ICollection.IsSynchronized => (this.sourceList as ICollection)?.IsSynchronized ?? false;
 		bool ICollection<T>.Remove(T item) => throw new InvalidOperationException();

Core/Collections/SortedObservableList.cs

@@ -590,7 +590,13 @@ public bool SortAt(int index)
 
 		// Interface implementations.
 		void ICollection<T>.Add(T value) => this.Add(value);
-		void ICollection.CopyTo(Array array, int index) => this.CopyTo((T[])array, index);
+		void ICollection.CopyTo(Array array, int index)
+		{
+			if (array is T[] targetArray)
+				this.list.CopyTo(targetArray, index);
+			else
+				((ICollection)this.list).CopyTo(array, index);
+		}
 		bool ICollection<T>.IsReadOnly => false;
 		bool ICollection.IsSynchronized => false;
 		object ICollection.SyncRoot => this;

Core/Collections/TypeConvertedObservableList.cs

@@ -243,7 +243,13 @@ void RebuildList()
 		// Interface implementations.
 		void ICollection<TDest>.Add(TDest value) => throw new InvalidOperationException();
 		void ICollection<TDest>.Clear() => throw new InvalidOperationException();
-		void ICollection.CopyTo(Array array, int index) => this.CopyTo((TDest[])array, index);
+		void ICollection.CopyTo(Array array, int index)
+		{
+			if (array is TDest[] targetArray)
+				this.list.CopyTo(targetArray, index);
+			else
+				((ICollection)this.list).CopyTo(array, index);
+		}
 		bool ICollection<TDest>.IsReadOnly => true;
 		bool ICollection.IsSynchronized => (this.sourceList as ICollection)?.IsSynchronized ?? false;
 		bool ICollection<TDest>.Remove(TDest item) => throw new InvalidOperationException();