OpenTween/ImageListViewItem.cs

   1 // OpenTween - Client of Twitter
   2 // Copyright (c) 2007-2011 kiri_feather (@kiri_feather) <kiri.feather@gmail.com>
   3 //           (c) 2008-2011 Moz (@syo68k)
   4 //           (c) 2008-2011 takeshik (@takeshik) <http://www.takeshik.org/>
   5 //           (c) 2010-2011 anis774 (@anis774) <http://d.hatena.ne.jp/anis774/>
   6 //           (c) 2010-2011 fantasticswallow (@f_swallow) <http://twitter.com/f_swallow>
   7 //           (c) 2011      Egtra (@egtra) <http://dev.activebasic.com/egtra/>
   8 // All rights reserved.
   9 //
  10 // This file is part of OpenTween.
  11 //
  12 // This program is free software; you can redistribute it and/or modify it
  13 // under the terms of the GNU General Public License as published by the Free
  14 // Software Foundation; either version 3 of the License, or (at your option)
  15 // any later version.
  16 //
  17 // This program is distributed in the hope that it will be useful, but
  18 // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  20 // for more details.
  21 //
  22 // You should have received a copy of the GNU General Public License along
  23 // with this program. If not, see <http://www.gnu.org/licenses/>, or write to
  24 // the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  25 // Boston, MA 02110-1301, USA.
  26
  27 using System;
  28 using System.Net.Http;
  29 using System.Runtime.Serialization;
  30 using System.Threading.Tasks;
  31 using System.Windows.Forms;
  32
  33 namespace OpenTween
  34 {
  35     [Serializable]
  36     public class ImageListViewItem : ListViewItem
  37     {
  38         protected readonly ImageCache imageCache;
  39         protected readonly string imageUrl;
  40
  41         /// <summary>
  42         /// 状態表示に使用するアイコンのインデックスを取得・設定する。
  43         /// </summary>
  44         /// <remarks>
  45         /// StateImageIndex は不必要な処理が挟まるため、使用しないようにする。
  46         /// </remarks>
  47         public int StateIndex { get; set; }
  48
  49         private WeakReference imageReference = new WeakReference(null);
  50         private Task imageTask = null;
  51
  52         public event EventHandler ImageDownloaded;
  53
  54         public ImageListViewItem(string[] items)
  55             : this(items, null, null)
  56         {
  57         }
  58
  59         public ImageListViewItem(string[] items, ImageCache imageCache, string imageUrl)
  60             : base(items)
  61         {
  62             this.imageCache = imageCache;
  63             this.imageUrl = imageUrl;
  64             this.StateIndex = -1;
  65
  66             var image = imageCache?.TryGetFromCache(imageUrl);
  67
  68             if (image != null)
  69                 this.imageReference.Target = image;
  70         }
  71
  72         protected ImageListViewItem(SerializationInfo info, StreamingContext context)
  73             : base(info, context)
  74         {
  75         }
  76
  77         public Task GetImageAsync(bool force = false)
  78         {
  79             if (this.imageTask == null || this.imageTask.IsCompleted)
  80             {
  81                 this.imageTask = this.GetImageAsyncInternal(force);
  82             }
  83
  84             return this.imageTask;
  85         }
  86
  87         private async Task GetImageAsyncInternal(bool force)
  88         {
  89             if (string.IsNullOrEmpty(this.imageUrl))
  90                 return;
  91
  92             if (!force && this.imageReference.Target != null)
  93                 return;
  94
  95             try
  96             {
  97                 var image = await this.imageCache.DownloadImageAsync(this.imageUrl, force);
  98
  99                 this.imageReference.Target = image;
 100
 101                 if (this.ListView == null || !this.ListView.Created || this.ListView.IsDisposed)
 102                     return;
 103
 104                 if (this.Index < this.ListView.VirtualListSize)
 105                 {
 106                     this.ListView.RedrawItems(this.Index, this.Index, true);
 107
 108                     this.ImageDownloaded?.Invoke(this, EventArgs.Empty);
 109                 }
 110             }
 111             catch (HttpRequestException) { }
 112             catch (InvalidImageException) { }
 113             catch (TaskCanceledException) { }
 114         }
 115
 116         public MemoryImage Image
 117             => (MemoryImage)this.imageReference.Target;
 118
 119         public Task RefreshImageAsync()
 120         {
 121             this.imageReference.Target = null;
 122             return this.GetImageAsync(true);
 123         }
 124     }
 125 }