WPF 使用 RenderTargetBitmap 快速截图出现 COMException 提示

本文告诉大家一个最简单步骤让 RenderTargetBitmap 出现 COMException 提示

只需要在界面添加一个 ListView 绑定图片，然后在后台不断刷新列表就可以

<ListView Margin="10,10,10,10" ItemsSource="{Binding DeagernereDechuno}">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Grid Margin="10,10,10,10">
                        <Image Source="{Binding}"></Image>
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

在后台创建 DeagernereDechuno 列表

public ObservableCollection<ImageSource> DeagernereDechuno { get; set; }=new ObservableCollection<ImageSource>();

在 Load 之后调用函数 WarwairJorkasou 不断截图

public MainWindow()
        {
            InitializeComponent();
            DataContext = this;


            Loaded += (s, e) =>
            {
                 WarwairJorkasou();
            };
        }

在 WarwairJorkasou 调用循环进行截图，很快就可以看到下面提示

System.Runtime.InteropServices.COMException: MILERR_WIN32ERROR

异常堆栈

System.Runtime.InteropServices.COMException (0x88980003): MILERR_WIN32ERROR (异常来自 HRESULT:0x88980003)
   在 System.Windows.Media.Imaging.RenderTargetBitmap.FinalizeCreation()
   在 System.Windows.Media.Imaging.RenderTargetBitmap..ctor(Int32 pixelWidth, Int32 pixelHeight, Double dpiX, Double dpiY, PixelFormat pixelFormat)

截图的代码

private async void WarwairJorkasou()
        {
            var ran = new Random();

            while (true)
            {
                await Task.Delay(10).ContinueWith(_ =>
                {
                    DeagernereDechuno.Clear();
                    var n = ran.Next(int.MaxValue / 10);
                    for (int i = n; i < n + 1000; i++)
                    {
                        try
                        {
                            DrawingVisual drawingVisual = new DrawingVisual();
                            DrawingContext drawingContext = drawingVisual.RenderOpen();

                            var text = new FormattedText(i.ToString(),
                                CultureInfo.GetCultureInfo("zh-cn"),
                                FlowDirection.LeftToRight,
                                new Typeface("Verdana"),
                                36, Brushes.Black);
                            drawingContext.DrawText(text,
                                new Point(0, 0));
                
                            drawingContext.Close();

                            var image = new RenderTargetBitmap((int) text.Width, (int) text.Height, 96, 96, PixelFormats.Pbgra32);
                            image.Render(drawingVisual);

                            DeagernereDechuno.Add(image);
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine(e);
                        }
                    }
                }, TaskScheduler.FromCurrentSynchronizationContext());
            }
        }

运行程序大概在 300M 左右就会出现 COMException 提示

System.Runtime.InteropServices.COMException (0x88980003): MILERR_WIN32ERROR (Exception from HRESULT: 0x88980003)

RenderTargetBitmap throws COM exception when created too fast: MILERR_WIN32ERROR (Exception from HRESULT: 0x88980003)

代码请看 https://github.com/dotnet-campus/wpf-issues/tree/master/RenderTargetBitmapThrowsCOMExceptionWhenCreatedTooFast