// Copyright (c) The Avalonia Project. All rights reserved.
// Licensed under the MIT license. See licence.md file in the project root for full license information.

using System;
using Avalonia.Rendering;
using Avalonia.VisualTree;

namespace Avalonia
{
    /// <summary>
    /// Holds the event arguments for the <see cref="Visual.AttachedToVisualTree"/> and 
    /// <see cref="Visual.DetachedFromVisualTree"/> events.
    /// </summary>
    public class VisualTreeAttachmentEventArgs : EventArgs
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="VisualTreeAttachmentEventArgs"/> class.
        /// </summary>
        /// <param name="parent">The parent that the visual is being attached to or detached from.</param>
        /// <param name="root">The root visual.</param>
        public VisualTreeAttachmentEventArgs(IVisual parent, IRenderRoot root)
        {
            Contract.Requires<ArgumentNullException>(parent != null);
            Contract.Requires<ArgumentNullException>(root != null);

            Parent = parent;
            Root = root;
        }

        /// <summary>
        /// Gets the parent that the visual is being attached to or detached from.
        /// </summary>
        public IVisual Parent { get; }

        /// <summary>
        /// Gets the root of the visual tree that the visual is being attached to or detached from.
        /// </summary>
        public IRenderRoot Root { get; }
    }
}