dotnet/wpf · error · ArgumentNullException

throw new ArgumentNullException(nameof(section));

Error message

throw new ArgumentNullException(nameof(section));

What it means

CreateBitmapSourceFromMemorySection throws ArgumentNullException when the win32 file-mapping handle passed as `section` is IntPtr.Zero. A WPF InteropBitmap must be backed by a real shared-memory section handle, so a null/zero handle cannot be used to create one.

Solutions

1. Check the handle returned from CreateFileMapping/CreateDC/etc. for IntPtr.Zero or failure before passing it to CreateBitmapSourceFromMemorySection
2. Ensure the shared-memory section is actually created (correct size, valid PAGE_* protection, flProtect not 0)
3. If using System.IO.MemoryMappedFiles, open the MemoryMappedFile first and pass its SafeMemoryMappedFileHandle, verifying it is not IsInvalid/IsClosed
4. If the source may legitimately be absent, branch on IntPtr.Zero and skip/defer the bitmap creation instead of calling the API

Example fix

// before
IntPtr section = CreateFileMapping(new IntPtr(-1), IntPtr.Zero, 0x04, 0, size, null);
var source = Imaging.CreateBitmapSourceFromMemorySection(section, w, h, PixelFormats.Pbgra32, stride, 0);
// after
IntPtr section = CreateFileMapping(new IntPtr(-1), IntPtr.Zero, 0x04, 0, size, null);
if (section == IntPtr.Zero)
    throw new Win32Exception(Marshal.GetLastWin32Error(), "CreateFileMapping failed");
var source = Imaging.CreateBitmapSourceFromMemorySection(section, w, h, PixelFormats.Pbgra32, stride, 0);

if (section == IntPtr.Zero) throw new InvalidOperationException("Shared-memory section handle not created");
// else safe to call Imaging.CreateBitmapSourceFromMemorySection(...)

static bool IsValidSectionHandle(IntPtr h) => h != IntPtr.Zero;

try { var bmp = Imaging.CreateBitmapSourceFromMemorySection(section, w, h, fmt, stride, off); }
catch (ArgumentNullException ex) { /* handle missing section handle */ }

When it happens

Trigger: Calling Imaging.CreateBitmapSourceFromMemorySection with a handle that is IntPtr.Zero — typically because CreateFileMapping (or the memory-mapped-file SafeFileHandle) returned null/failed and the failure was never checked before passing the handle on.

Common situations: Interoperating with GDI/memory-mapped buffers shared with another process; the foreign process never created or closed the section, CreateFileMapping failed due to insufficient permissions or memory, or a NativeMemory/MemoryMappedFile handle was default-initialized instead of opened.

Related errors

• ArgumentNullException (buffer/sourceBuffer was IntPtr.Zero)
• 0x80070057
• annotation component
• ArgumentNullException
• ArgumentNullException(argName)

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/8aebcecfb641a810. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/InterOp/Imaging.cs:106

        /// <param name="pixelHeight"></param>
        /// <param name="format"></param>
        /// <param name="stride"></param>
        /// <param name="offset"></param>
        /// <remarks>
        ///     Callers must have UnmanagedCode permission to call this API.
        /// </remarks>
        public static unsafe BitmapSource CreateBitmapSourceFromMemorySection(
            IntPtr section,
            int pixelWidth,
            int pixelHeight,
            Media.PixelFormat format,
            int stride,
            int offset)
        {

            if (section == IntPtr.Zero)
            {
                throw new ArgumentNullException(nameof(section));
            }

            return new InteropBitmap(section, pixelWidth, pixelHeight, format, stride, offset);
        }
}
}

View on GitHub (pinned to 81131a70a4)