内存泄漏,但在哪里？

Question

我无法理解这里泄漏的是什么

using GDI = System.Drawing;

public partial class MainWindow : Window
{
    [DllImport("gdi32.dll")]
    private static extern bool DeleteObject(IntPtr obj);

    public MainWindow()
    {
        InitializeComponent();

        var timer = new DispatcherTimer() { Interval = TimeSpan.FromMilliseconds(50) };
        timer.Tick += (s, a) =>
        {
            using (var bitmap = new GDI.Bitmap(1000, 1000))
            {
                var hbitmap = bitmap.GetHbitmap();
                var image = Imaging.CreateBitmapSourceFromHBitmap(hbitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
                image.Freeze();
                DeleteObject(hbitmap);
            }
        };
    timer.Start();
}

bitmap？弃置.hbitmap？删除.image？冷冻,但事实并非如此IDisposable.

事实是,这个应用程序会崩溃(在运行约20秒后在我的电脑上)

System.Drawing.dll中发生了未处理的"System.OutOfMemoryException"类型异常

附加信息:内存不足.

有任何想法吗？

Answer 1

据我所知,没有泄漏.问题是你要快速分配大型C#对象而垃圾收集器为时已晚了？

以下是一些相关主题:

在C#中进行大型,快速和频繁的内存分配时避免OutOfMemoryException

这是有用的线程:

即使在需要时也不会发生垃圾收集

如果您踢GC.Collect(代数为0..3),您的内存消耗将被修复:

    while (true)
    {
        Thread.Sleep(5);

        using (var bitmap = new GDI.Bitmap(1000, 1000))
        {
            var hbitmap = bitmap.GetHbitmap();
            var image = Imaging.CreateBitmapSourceFromHBitmap(hbitmap, IntPtr.Zero, Int32Rect.Empty,
                BitmapSizeOptions.FromEmptyOptions());

            image.Freeze();


          DeleteObject(hbitmap);
        }

        Console.WriteLine("Current memory consumption" + GC.GetTotalMemory(false));
        GC.Collect(3);
    }

并输出:

Current memory consumption156572
Current memory consumption156572
Current memory consumption156572
Current memory consumption156572

真正的问题是GC不知道你的非托管分配,即使你释放它们.您需要添加内存压力并让GC了解它:

 var width = 1000;
                var height = 1000;

                using (var bitmap = new GDI.Bitmap(width, height))
                {
                    var hbitmap = bitmap.GetHbitmap();
                    var allocatedSize = width*height*4; // each pixel takes ~4 bytes?!
                    GC.AddMemoryPressure(allocatedSize);

                    var image = Imaging.CreateBitmapSourceFromHBitmap(hbitmap, IntPtr.Zero, Int32Rect.Empty,
                        BitmapSizeOptions.FromEmptyOptions());

                    image.Freeze();


                    DeleteObject(hbitmap);
                    GC.RemoveMemoryPressure(allocatedSize);
                }

让GC了解底层非托管内存有助于确保GC在正确的位置启动.