Tiff Image：如何在.Net中以编程方式设置mulltipage tiff的元数据？

Question

我正在尝试为多页tiff图像设置元数据。以下是单页tiff图像的代码段设置元数据。

            Bitmap imageSource = img as Bitmap; // img is an original singlepage tiff image
            Bitmap tempBitmap = new Bitmap(imageSource.Width, imageSource.Height);

            try
            {
                ImageCodecInfo encoderInfo = GetEncoderInfo("image/tiff");

                EncoderParameters encoderParams = new EncoderParameters(2);                 
                EncoderParameter parameter = new EncoderParameter(System.Drawing.Imaging.Encoder.Compression, (long)EncoderValue.CompressionCCITT3);
                encoderParams.Param[0] = parameter;

                parameter = new EncoderParameter(System.Drawing.Imaging.Encoder.SaveFlag,(long)EncoderValue.Flush);
                encoderParams.Param[1] = parameter;

                //Set the resolution as of the image file
                tempBitmap.SetResolution(imageSource.HorizontalResolution, imageSource.VerticalResolution);

                using (Graphics graphics = Graphics.FromImage(tempBitmap))
                {
                    //Draw the image in the Empty bitmap by passing original imageSource
                    graphics.DrawImage(imageSource, 0, 0, (float)imageSource.Width, (float)imageSource.Height);
                }

                string strSign = "I am author";

                PropertyItem propItem = img.PropertyItems[0];
                propItem.Id = 315;  // this is called 'Author'
                propItem.Type = 2;
                propItem.Value = System.Text.Encoding.UTF8.GetBytes(strSign + "\0");//signature;
                propItem.Len = propItem.Value.Length;
                ((Image)tempBitmap).SetPropertyItem(propItem);
                img.Dispose();
                ((Image)tempBitmap).Save("sample.tif", encoderInfo, encoderParams);
            }
            catch (Exception ex)
            {                   
            }

以上代码适用于单页图像，但无法实现多页图像的设置元数据。我对此有点新鲜，任何可用于实现多页tiff图像设置元数据的有用链接或库都会有所帮助。