WPF Book Reader

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

namespace BookReader
{
	internal class ImageCache
	{
		internal class ImgInfo
		{
			public ImgInfo(BitmapImage image, object tag)
			{
				_Image = image;
				_Tag = tag;
			}
			public object _Tag = null;
			public BitmapImage _Image = null;
			public DateTime _LastAcces = DateTime.Now;
		}

		public ImageCache()
		{
			_ImagesCache = new List<ImgInfo>();
		}

		private long _TotalSize;
		private List<ImgInfo> _ImagesCache;

		public void Clear()
		{
			_ImagesCache.Clear();
		}

		public bool Find(object tag)
		{
			ImgInfo inf = _ImagesCache.Find(delegate(ImgInfo record)
			   {
				 if (record._Tag == tag)
				 { return true; } 
				 return false;
			   });

			return inf != null; 
		}

		internal ImgInfo FindInfo(object tag)
		{
			ImgInfo inf = _ImagesCache.Find(delegate(ImgInfo record)
			{
				if (record._Tag == tag)
				{ return true; }
				return false;
			});

			return inf;
		}

		public BitmapImage GetImage(object tag)
		{
			ImgInfo ImgInfo = FindInfo(tag);
			if (ImgInfo != null)
			{
				ImgInfo._LastAcces = DateTime.Now;
				return ImgInfo._Image;
			}
			else
				return null;
		}

		public void Store(object tag, BitmapImage image)
		{
			_ImagesCache.Add(new ImgInfo( image, tag ));
		}

		public void ManageCache()
		{
			while (_ImagesCache.Count > Properties.Settings.Default.ImageCacheCount)
				_ImagesCache.Remove(_ImagesCache.First());

			_TotalSize = 0;

			for (int i = 0; i < Properties.Settings.Default.ImageCacheCount; i++)
			{
				if (_ImagesCache.Count > i)
				{
					if (_ImagesCache[i]._LastAcces < DateTime.Now.AddMinutes(-Properties.Settings.Default.ImageCacheDuration))
						_ImagesCache.Remove(_ImagesCache[i]);
				}
			}

			foreach( ImgInfo imgInfo in _ImagesCache )
				_TotalSize += imgInfo._Image.StreamSource.Length;

		}

		public string GetCacheInfo()
		{
			return string.Format("Cache Info : Image {0}/{1}; Size {2}", _ImagesCache.Count, Properties.Settings.Default.ImageCacheCount, _TotalSize);
		}
	}
}