c# - OutOfMemoryException when rendering TextBlock using WriteableBitmapEx -

i have fight outofmemoryexception again.

i have code snippet render images using writeablebitmapex in windows phone background agent task (which have memory usage limit approach 10m).

the following works fine:

deployment.current.dispatcher.begininvoke(() => {     var wbbg = bitmapfactory.new(0, 0);     var bmp = bitmapfactory.new(0, 0);     (int = 0; < 30; i++)     {         using (var iso = isolatedstoragefile.getuserstoreforapplication())         {             wbbg = bitmapfactory.new(0, 0).fromcontent("assets/image" + + ".jpg");                                       wbbg.invalidate();              (int j = 0; j < 6; j++)             {                 bmp = bitmapfactory.new(0, 0).fromcontent("assets/" + j + ".png");                 bmp = bmp.resize(60, 60, writeablebitmapextensions.interpolation.bilinear);                  wbbg.blit(new rect(j * 65, 0, 60, 60), bmp, new rect(0, 0, 60, 60));                 wbbg.invalidate();             }             string filenamebg = "/shared/" + + ".jpg";             using (var stream = iso.createfile(filenamebg))             {                 wbbg.savejpeg(stream, 480, 800, 0, 85);                 stream.close();             }             wbbg = null;             gc.collect();             gc.waitforpendingfinalizers();         }     }     notifycomplete(); }); 

however, if add or change use textblock in loop, fail in 2nd loop withoutofmemoryexception:

deployment.current.dispatcher.begininvoke(() => {     var wbbg = bitmapfactory.new(0, 0);     textblock tb;     (int = 0; < 30; i++)     {         using (var iso = isolatedstoragefile.getuserstoreforapplication())         {             wbbg = bitmapfactory.new(0, 0).fromcontent("assets/image" + + ".jpg");                              //the above line thrown outofmemoryexception in 2nd loop                                    wbbg.invalidate();              (int j = 0; j < 6; j++)             {                 tb = new textblock(){                     text = j.tostring(),                     //fontsize = 13,                     //height = 20,                     //width = 240,                     //fontweight = system.windows.fontweights.bold,                     //horizontalalignment = system.windows.horizontalalignment.center,                     //foreground = new solidcolorbrush(colors.white)                 };                 wbbg.render(tb, new translatetransform() { x = j*65, y = 350 });                 wbbg.invalidate();                 tb = null;             }             string filenamebg = "/shared/" + + ".jpg";             using (var stream = iso.createfile(filenamebg))             {                 wbbg.savejpeg(stream, 480, 800, 0, 85);                 stream.close();             }             wbbg = null;             gc.collect();             gc.waitforpendingfinalizers();         }     }     notifycomplete(); }); 

any idea why textblock cause more memory usage?

furthermore, don't see there better method render text on images.

also textblock not idisposable.

well, that's opinions, wrong, i'd appreciate help, thank!

i don't know library have forgot release resources when aren't in use anymore try this:

        (var = 0; < 30; i++)         {             using (var iso = isolatedstoragefile.getuserstoreforapplication())             {                 using (var wbbg = bitmapfactory.new(0, 0).fromcontent("assets/image" + + ".jpg"))                 {                     wbbg.invalidate();                      (int j = 0; j < 6; j++)                     {                         var tb = new textblock()                         {                             text = j.tostring(),                             //fontsize = 13,                             //height = 20,                             //width = 240,                             //fontweight = system.windows.fontweights.bold,                             //horizontalalignment = system.windows.horizontalalignment.center,                             //foreground = new solidcolorbrush(colors.white)                         };                         wbbg.render(tb, new translatetransform() { x = j * 65, y = 350 });                         wbbg.invalidate();                     }                     using (var stream = iso.createfile("/shared/" + + ".jpg"))                     {                         wbbg.savejpeg(stream, 480, 800, 0, 85);                     }                 }             }         }