OutOfMemoryException in WPF RenderTargetBitmap.Render

See more:

C#3.0

.NET3.5

C#

.NET

WPF

I have a WPF that leaks a lot of memory calling RenderTargetBitmap.Render. I see posts all over the internet about how this was supposed to be fixed but isn't. I have done a lot of looking but can't find a workaround. This is .net 3.5 sp1

I subclassed the inkCanvas object to handle multi-page tiffs. I save each page as a bitmapImage in an array. I also save a corresponding StrokesCollection array. When it is time to save the multi-tiff I call a method called BindImage that loads the image and corresponding StrokesCollection into the canvas and saves it as a page of a tiff.

the line:

rtb.Render(this);

leaks memory at each page iteration. My code works well with smaller tiffs, but those with many pages cause OutOfMemoryException.

I have tried:
-recompiling under .net 4
-creating a new inkcanvas on the fly, then calling render on it and destroying it, then calling carbage collection.

private void BindImage()
       {
           System.Windows.Controls.Image imgTemp;
           bmpSavePages = new BitmapImage[bmpPages.Length];

           for (int i = 0; i < bmpPages.Length; i++)
           {
               this.Children.Clear();
               this.Strokes.Clear();

               imgTemp = new System.Windows.Controls.Image();

               imgTemp.Source = bmpPages[i];
               this.Children.Add(imgTemp);
               this.Strokes.Add(strWriting[i]);

               this.Children[0].UpdateLayout();
               MemoryStream ms = new MemoryStream();

               RenderTargetBitmap rtb = new RenderTargetBitmap((int)dbImageWidth, (int)dbImageHeight, dbPixelWidth, dbPixelDepth, pxfFormat);

               rtb.Render(this);

               BitmapEncoder encoder = new TiffBitmapEncoder();
               try
               {
                   encoder.Frames.Add(BitmapFrame.Create(rtb));
                   encoder.Save(ms);

                   bmpSavePages[i] = new BitmapImage();
                   bmpSavePages[i].BeginInit();
                   bmpSavePages[i].StreamSource = ms;
                   bmpSavePages[i].CacheOption = BitmapCacheOption.OnLoad;
                   bmpSavePages[i].DecodePixelHeight = (int)dbImageHeight;
                   bmpSavePages[i].EndInit();
               }
               catch (Exception e)
               {
                   System.Windows.MessageBox.Show("There was an error binding the final image.\n\n" + e.Message);
               }
               finally
               {
                   ms.Dispose();
                   ms = null;
               }
           }
       }