获取文档内容缩略图的方法

1:将文档用虚拟打印转换成.tif文件.

2.分割.tif文件，取第一页并生成缩略图,示例代码如下：

 

using (image = Image.FromFile(tagFilename))
                {
                    Guid guid = (Guid)image.FrameDimensionsList.GetValue(0);
                    FrameDimension dimension = new FrameDimension(guid);
                    int pageCount = image.GetFrameCount(dimension);
                    image.SelectActiveFrame(dimension, 0);
                    image=image.GetThumbnailImage(100, 100, new Image.GetThumbnailImageAbort(delegate() { return false; }), IntPtr.Zero);
                    image.Save(tifFirstFrameBuff, ImageFormat.Gif);
                    image.Dispose();
                }