QuickLook/QuickLook.Plugin/QuickLook.Plugin.ArchiveViewer/Extensions.cs

// Copyright © 2017 Paddy Xu
// 
// This file is part of QuickLook program.
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Media;

namespace QuickLook.Plugin.ArchiveViewer
{
    public static class Extensions
    {
        public static void ForEach<T>(this IEnumerable<T> enumeration, Action<T> action)
        {
            foreach (var item in enumeration)
                action(item);
        }

        public static T GetDescendantByType<T>(this Visual element) where T : class
        {
            if (element == null)
                return default(T);
            if (element.GetType() == typeof(T))
                return element as T;

            T foundElement = null;
            (element as FrameworkElement)?.ApplyTemplate();

            for (var i = 0; i < VisualTreeHelper.GetChildrenCount(element); i++)
            {
                var visual = VisualTreeHelper.GetChild(element, i) as Visual;
                foundElement = visual.GetDescendantByType<T>();
                if (foundElement != null)
                    break;
            }
            return foundElement;
        }
    }
}