What causes "Vulkan D3DDevice wasn't created" in AvaloniaUI/Avalonia?

Ensure vk.D3DDevice is created before VulkanImage export on Windows — create the D3D11On12 device and assign it so Handle is non-null.

AvaloniaUI/Avalonia · error · NotSupportedException

Vulkan D3DDevice wasn't created

Error message

Vulkan D3DDevice wasn't created

What it means

On Windows the sample shares a D3D11 texture with Vulkan by importing a DXGI shared handle, which requires a Vulkan D3D device (vk.D3DDevice) created via D3D11On12 / VkD3D11ExternalMemory. The NotSupportedException fires when that interop D3D device is null while the code path needs it (handleType == D3D11TextureBit && exportable). It indicates the Windows-D3D external-memory bridge was never set up.

Source

Thrown at samples/GpuInterop/VulkanDemo/VulkanImage.cs:143

                    out var memoryRequirements);

                var dedicatedAllocation = new MemoryDedicatedAllocateInfoKHR
                {
                    SType = StructureType.MemoryDedicatedAllocateInfoKhr, Image = image
                };

                var fdExport = new ExportMemoryAllocateInfo
                {
                    HandleTypes = handleType,
                    SType = StructureType.ExportMemoryAllocateInfo,
                    PNext = &dedicatedAllocation
                };

                ImportMemoryWin32HandleInfoKHR handleImport = default;
                if (handleType == ExternalMemoryHandleTypeFlags.D3D11TextureBit && exportable)
                {
                    if (vk.D3DDevice.Handle == null)
                        throw new NotSupportedException("Vulkan D3DDevice wasn't created");
                    _d3dTexture2D = D3DMemoryHelper.CreateMemoryHandle(vk.D3DDevice, size, Format);

                    handleImport = new ImportMemoryWin32HandleInfoKHR
                    {
                        PNext = &dedicatedAllocation,
                        SType = StructureType.ImportMemoryWin32HandleInfoKhr,
                        HandleType = ExternalMemoryHandleTypeFlags.D3D11TextureBit,
                        Handle = CreateDxgiSharedHandle()
                    };
                }

                var memoryAllocateInfo = new MemoryAllocateInfo
                {
                    PNext =
                        exportable ? handleImport.Handle != IntPtr.Zero ? &handleImport : &fdExport : null,
                    SType = StructureType.MemoryAllocateInfo,
                    AllocationSize = memoryRequirements.Size,
                    MemoryTypeIndex = (uint)VulkanMemoryHelper.FindSuitableMemoryTypeIndex(

View on GitHub (pinned to 11c5427268)

Solutions

Ensure vk.D3DDevice is created before VulkanImage export on Windows — create the D3D11On12 device and assign it so Handle is non-null.
Verify the instance/device enable VK_KHR_external_memory, VK_KHR_external_memory_win32, and the dedicated-allocation extension.
If D3D sharing is not needed, do not set exportable with D3D11TextureBit (avoid this code path).
Run on Windows 10+ with a driver that exposes the external-memory-win32 extension.

Example fix

// before
if (vk.D3DDevice.Handle == null)
    throw new NotSupportedException("Vulkan D3DDevice wasn't created");

// after (fail early with actionable guidance at device setup)
if (vk.D3DDevice?.Handle is null)
    throw new NotSupportedException(
        "Vulkan D3D interop device wasn't created. Enable VK_KHR_external_memory_win32 and create the D3D11On12 device before exporting a shared D3D11 texture.");

Defensive patterns

Strategy: validation

Validate before calling

// before exporting a shared D3D11 texture
if (OperatingSystem.IsWindows() && exportable && handleType == ExternalMemoryHandleTypeFlags.D3D11TextureBit
    && vk.D3DDevice?.Handle is null)
{
    // skip the D3D export path or create the device first
}

Type guard

static bool CanExportD3D11(VkHandle vk) => vk.D3DDevice?.Handle is not null;

Try / catch

try { /* image creation/export that hits the D3D path */ }
catch (NotSupportedException ex) when (ex.Message.Contains("D3DDevice"))
{ /* fall back to a non-shared Vulkan image */ }

Prevention

Create the D3D11On12 device before image export on Windows.
Verify VK_KHR_external_memory_win32 is enabled on instance+device.
Do not set D3D11TextureBit+exportable unless you need D3D sharing.

When it happens

Trigger: Calling VulkanImage creation/export with ExternalMemoryHandleTypeFlags.D3D11TextureBit set as exportable, on Windows, before vk.D3DDevice has been initialized. Happens when the Vulkan demo's D3D interop device was skipped or failed silently.

Common situations: Running the demo on a system lacking VK_KHR_external_memory_win32; failing to create the D3D11On12 device; copy-paste of image-export code without setting up D3DMemoryHelper's backing device; Windows N editions missing d3d11.

Related errors

AI-assisted analysis of AvaloniaUI/Avalonia@11c5427268 (2026-08-13). Data as JSON: /api/errors/9223282665062981. Report an issue: GitHub.