添加项目文件。

WpfAnimatedGif/Decoding/GifCommentExtension.cs

@@ -0,0 +1,37 @@
+using System.IO;
+using System.Text;
+
+namespace WpfAnimatedGif.Decoding
+{
+    internal class GifCommentExtension : GifExtension
+    {
+        internal const int ExtensionLabel = 0xFE;
+
+        public string Text { get; private set; }
+
+        private GifCommentExtension()
+        {
+        }
+
+        internal override GifBlockKind Kind
+        {
+            get { return GifBlockKind.SpecialPurpose; }
+        }
+
+        internal static GifCommentExtension ReadComment(Stream stream)
+        {
+            var comment = new GifCommentExtension();
+            comment.Read(stream);
+            return comment;
+        }
+
+        private void Read(Stream stream)
+        {
+            // Note: at this point, the label (0xFE) has already been read
+
+            var bytes = GifHelpers.ReadDataBlocks(stream, false);
+            if (bytes != null)
+                Text = Encoding.ASCII.GetString(bytes);
+        }
+    }
+}