dotnet/wpf · error · ArgumentNullException

throw new ArgumentNullException(nameof(bitmap));

Error message

throw new ArgumentNullException(nameof(bitmap));

What it means

Imaging.CriticalCreateBitmapSourceFromHBitmap (reached via the public CreateBitmapSourceFromHBitmap) requires a non-zero HBITMAP. Passing IntPtr.Zero throws ArgumentNullException for the 'bitmap' parameter because a null bitmap cannot back an InteropBitmap.

Solutions

1. Check hBitmap != IntPtr.Zero before calling CreateBitmapSourceFromHBitmap and handle the failure (e.g. retry capture)
2. Verify the GDI call that produced the HBITMAP (GetLastError on failure)
3. Remember to DeleteObject the HBITMAP after creating the source to avoid leaks

Example fix

// before
var bmp = Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
// after
if (hBitmap == IntPtr.Zero) throw new InvalidOperationException("bitmap creation failed");
var bmp = Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());

if (hBitmap == IntPtr.Zero) throw new InvalidOperationException("GDI bitmap creation failed");

bool IsValidHandle(IntPtr h) => h != IntPtr.Zero;

try { Imaging.CreateBitmapSourceFromHBitmap(hBitmap, ...); } catch (ArgumentNullException) { /* retry capture or use placeholder */ }

When it happens

Trigger: Calling Imaging.CreateBitmapSourceFromHBitmap(IntPtr.Zero, ...) — often when CreateCompatibleBitmap/LoadImage/BmpFromScreen failed and the zero handle was passed through unchecked.

Common situations: Screen-capture code where GetDC/CreateCompatibleBitmap failed under secure desktop or GDI resource exhaustion; unmarshal of a bitmap handle that came back NULL from native code.

Related errors

• throw new ArgumentNullException(nameof(icon));
• annotation component
• ArgumentNullException
• ArgumentNullException(argName)
• ArgumentNullException("characterBufferReference.CharacterBuf…

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/9485c82939259496. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/InterOp/Imaging.cs:54

        /// <summary>
        /// Construct an Bitmap from a HBITMAP.
        /// </summary>
        /// <param name="bitmap"></param>
        /// <param name="palette"></param>
        /// <param name="sourceRect"></param>
        /// <param name="sizeOptions"></param>
        /// <param name="alphaOptions"></param>
        internal static unsafe BitmapSource CriticalCreateBitmapSourceFromHBitmap(
            IntPtr bitmap,
            IntPtr palette,
            Int32Rect sourceRect,
            BitmapSizeOptions sizeOptions,
            WICBitmapAlphaChannelOption alphaOptions)
        {
            if (bitmap == IntPtr.Zero)
            {
                throw new ArgumentNullException(nameof(bitmap));
            }

            return new InteropBitmap(bitmap, palette, sourceRect, sizeOptions, alphaOptions); // use the critical version
        }
        
        /// <summary>
        /// Construct an Bitmap from a HICON.
        /// </summary>
        /// <param name="icon"></param>
        /// <param name="sourceRect"></param>
        /// <param name="sizeOptions"></param>
        /// <remarks>
        ///     Callers must have UnmanagedCode permission to call this API.
        /// </remarks>
        public static unsafe BitmapSource CreateBitmapSourceFromHIcon(
            IntPtr icon,
            Int32Rect sourceRect,
            BitmapSizeOptions sizeOptions)

View on GitHub (pinned to 81131a70a4)