WPF CreateBitmapSourceFromHBitmap() memory leak

Question

I need to draw an image pixel by pixel and display it inside a WPF. I am attempting to do this by using a System.Drawing.Bitmap then using CreateBitmapSourceFromHBitmap() to create a BitmapSource for a WPF Image control. I have a memory leak somewhere because when the CreateBitmapSourceFromBitmap() is called repeatedly the memory usage goes up and does not drop off until the application is ended. If I don't call CreateBitmapSourceFromBitmap() there is no noticeable change in memory usage.

for (int i = 0; i < 100; i++) {     var bmp = new System.Drawing.Bitmap(1000, 1000);     var source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(         bmp.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty,         System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());     source = null;     bmp.Dispose();     bmp = null; } 

What can I do to free the BitmapSource memory?

Answer 1

MSDN for Bitmap.GetHbitmap() states:

Remarks

You are responsible for calling the GDI DeleteObject method to free the memory used by the GDI bitmap object.

So use the following code:

// at class level [System.Runtime.InteropServices.DllImport("gdi32.dll")] public static extern bool DeleteObject(IntPtr hObject);  // your code using (System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(1000, 1000))  {     IntPtr hBitmap = bmp.GetHbitmap();       try      {         var source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());     }     finally      {         DeleteObject(hBitmap);     } } 

I also replaced your Dispose() call by an using statement.