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 #nullable enable
  28
  29 using System;
  30 using System.Net.Http;
  31 using System.Runtime.Serialization;
  32 using System.Threading.Tasks;
  33 using System.Windows.Forms;
  34
  35 namespace OpenTween
  36 {
  37     [Serializable]
  38     public class ImageListViewItem : ListViewItem
  39     {
  40         protected readonly ImageCache? imageCache;
  41         protected readonly string? imageUrl;
  42
  43         /// <summary>
  44         /// 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。
  45         /// </summary>
  46         /// <remarks>
  47         /// StateImageIndex は不必要な処理が挟まるため、使用しないようにする。
  48         /// </remarks>
  49         public int StateIndex { get; set; }
  50
  51         private readonly WeakReference imageReference = new WeakReference(null);
  52         private Task? imageTask = null;
  53
  54         public event EventHandler ImageDownloaded;
  55
  56         public ImageListViewItem(string[] items)
  57             : this(items, null, null)
  58         {
  59         }
  60
  61         public ImageListViewItem(string[] items, ImageCache? imageCache, string? imageUrl)
  62             : base(items)
  63         {
  64             this.imageCache = imageCache;
  65             this.imageUrl = imageUrl;
  66             this.StateIndex = -1;
  67
  68             var image = imageUrl != null ? imageCache?.TryGetFromCache(imageUrl) : null;
  69
  70             if (image != null)
  71                 this.imageReference.Target = image;
  72         }
  73
  74         protected ImageListViewItem(SerializationInfo info, StreamingContext context)
  75             : base(info, context)
  76         {
  77         }
  78
  79         public Task GetImageAsync(bool force = false)
  80         {
  81             if (this.imageTask == null || this.imageTask.IsCompleted)
  82             {
  83                 this.imageTask = this.GetImageAsyncInternal(force);
  84             }
  85
  86             return this.imageTask;
  87         }
  88
  89         private async Task GetImageAsyncInternal(bool force)
  90         {
  91             if (string.IsNullOrEmpty(this.imageUrl) || this.imageCache == null)
  92                 return;
  93
  94             if (!force && this.imageReference.Target != null)
  95                 return;
  96
  97             try
  98             {
  99                 var image = await this.imageCache.DownloadImageAsync(this.imageUrl, force);
 100
 101                 this.imageReference.Target = image;
 102
 103                 if (this.ListView == null || !this.ListView.Created || this.ListView.IsDisposed)
 104                     return;
 105
 106                 if (this.Index < this.ListView.VirtualListSize)
 107                 {
 108                     this.ListView.RedrawItems(this.Index, this.Index, true);
 109
 110                     this.ImageDownloaded?.Invoke(this, EventArgs.Empty);
 111                 }
 112             }
 113             catch (HttpRequestException) { }
 114             catch (InvalidImageException) { }
 115             catch (TaskCanceledException) { }
 116         }
 117
 118         public MemoryImage Image
 119             => (MemoryImage)this.imageReference.Target;
 120
 121         public Task RefreshImageAsync()
 122         {
 123             this.imageReference.Target = null;
 124             return this.GetImageAsync(true);
 125         }
 126     }
 127 }