使用RenderTargetBitmap的WPF內存泄漏？

Question

我對我的WPF代碼中的內存泄漏有點困惑。我將一些3D幾何渲染爲幾個RenderTargetBitmaps，然後將其渲染到一個大的主RenderTargetBitmap。但是當我這樣做時，我會在一兩分鐘後得到一個內存泄漏，使我的應用程序崩潰。

我在下面的簡化代碼中重現了錯誤。

private void timer1_Tick(object sender, EventArgs e) { 
     // if first time, create final stitch bitmap and set UI image source 
     if (stitch == null) { 
      stitch = new RenderTargetBitmap(1280, 480, 96, 96, PixelFormats.Pbgra32); 
      myImage.Source = stitch; 
     } 

     // create visual and render to img1 
     Rect rect = new Rect(new Point(160, 100), new Size(320, 80)); 
     DrawingVisual dvis = new DrawingVisual(); 
     using (DrawingContext dc = dvis.RenderOpen()) { 
      dc.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect); 
     } 
     RenderTargetBitmap img1 = new RenderTargetBitmap(640, 480, 96, 96, PixelFormats.Pbgra32); 
     img1.Render(dvis); 

     // create visual and render to final stitch 
     DrawingVisual vis = new DrawingVisual(); 
     using (DrawingContext dc = vis.RenderOpen()) { 
      dc.DrawImage(img1, new Rect(0, 0, 640, 480)); 
     } 

     stitch.Clear(); 
     stitch.Render(vis); 
    } 

任何人都可以看到任何明顯的錯誤嗎？爲什麼這段代碼會有嚴重的內存泄漏？

Answer 1

如果你監視RenderTargetBitmap類的行爲使用資源監視器，你可以看到每次調用這個類時，你會失去500KB的內存。我對您的問題的回答是：不要使用RenderTargetBitmap類多次

你甚至不能釋放已使用的RenderTargetBitmap內存。

如果您確實需要使用RenderTargetBitmap類，只需在代碼結尾處添加這些行即可。

GC.Collect() 
GC.WaitForPendingFinalizers() 
GC.Collect() 

這可能是解決問題：

private void timer1_Tick(object sender, EventArgs e) { 
     // if first time, create final stitch bitmap and set UI image source 
     if (stitch == null) { 
      stitch = new RenderTargetBitmap(1280, 480, 96, 96, PixelFormats.Pbgra32); 
      myImage.Source = stitch; 
     } 

     // create visual and render to img1 
     Rect rect = new Rect(new Point(160, 100), new Size(320, 80)); 
     DrawingVisual dvis = new DrawingVisual(); 
     using (DrawingContext dc = dvis.RenderOpen()) { 
      dc.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect); 
     } 
     RenderTargetBitmap img1 = new RenderTargetBitmap(640, 480, 96, 96, PixelFormats.Pbgra32); 
     img1.Render(dvis); 

     // create visual and render to final stitch 
     DrawingVisual vis = new DrawingVisual(); 
     using (DrawingContext dc = vis.RenderOpen()) { 
      dc.DrawImage(img1, new Rect(0, 0, 640, 480)); 
     } 

     GC.Collect(); 
     GC.WaitForPendingFinalizers(); 
     GC.Collect(); 
     stitch.Clear(); 
     stitch.Render(vis); 
}