RE: [DisplayFusion 12.1.1] C# Script Compilation Fails with CS0012 – Missing System.Private.Windows.GdiPlus Reference

Binary Fortress Software — Fri, 13 Nov 2026 19:37:31 GMT

I was able to reproduce this here, so we've added it to our list to look into.

Thanks!

[DisplayFusion 12.1.1] C# Script Compilation Fails with CS0012 – Missing System.Private.Windows.GdiPlus Reference

Binary Fortress Software — Fri, 13 Nov 2026 11:20:30 GMT

Hi,

I'm experiencing a C# scripted function compilation issue in DisplayFusion 12.1.1, related to System.Drawing.Graphics, TextRenderer, and a missing System.Private.Windows.GdiPlus assembly reference.

The same code worked in DisplayFusion 12.0.2 but fails to compile in 12.1.1 after the migration to .NET 10.

Minimal Reproduction:

Create a new C# scripted function and paste the following code:

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using System;
using System.Drawing;
using System.Windows.Forms;

public static class DisplayFusionFunction
{
    public static void Run(IntPtr windowHandle)
    {
    }

    private static void Test(PaintEventArgs e)
    {
        TextRenderer.DrawText(
            e.Graphics,
            "Test",
            SystemFonts.DefaultFont,
            new Point(10, 10),
            Color.Black);

        TextRenderer.MeasureText(
            e.Graphics,
            "Test",
            SystemFonts.DefaultFont,
            new Size(200, 50));
    }
}

Even though Test() is never called, compilation fails.
The compiler reports:

The type 'IGraphics' is defined in an assembly that is not referenced.
You must add a reference to assembly
'System.Private.Windows.GdiPlus, Version=10.0.0.0,
Culture=neutral, PublicKeyToken=b77a5c561934e089'.

The same error occurs for `IGraphicsContextInfo`.

On one computer, manually adding `System.Private.Windows.GdiPlus.dll` through the DisplayFusion References dialog fails with:

The following reference(s) failed to be added successfully.
Please make sure that they are compatible with .NET 10
or .NET Standard 2.x.

- System.Private.CoreLib.dll

Could not load file or assembly
'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.2\System.Private.CoreLib.dll'.

The system cannot find the file specified.

Exception.HResult: COR_E_FILENOTFOUND (0x80070002)
FileNotFoundException.FileName:
C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.2\System.Private.CoreLib.dll

However, the file does exist (Test-Path returns True).

On another computer, adding the assembly does not produce this reference-loading error, but the script still fails to compile with the original IGraphics / IGraphicsContextInfo errors.

Tested Environments:

Computer 1:
- DisplayFusion 12.1.1
- .NET Runtime 10.0.2
- .NET SDK 10.0.102
- Windows Desktop Runtime 10.0.2
- The .NET 10 reference assembly exists at `C:\Program Files\dotnet\packs\Microsoft.WindowsDesktop.App.Ref\10.0.2\ref\net10.0\System.Private.Windows.GdiPlus.dll`

Computer 2:
- DisplayFusion 12.1.1
- .NET Runtime 10.0.14
- No .NET SDK installed
- Manually adding the assembly succeeds, but compilation still fails

Working Workaround

The following code compiles successfully:

IDeviceContext dc = (IDeviceContext)(object)e.Graphics;

TextRenderer.DrawText(
    dc,
    "Test",
    SystemFonts.DefaultFont,
    new Point(10, 10),
    Color.Black);

However, a direct assignment fails:

IDeviceContext dc = e.Graphics;

This strongly suggests a compile-time assembly reference resolution issue rather than a runtime issue.

The workaround is functional, but I would prefer not to rely on an unnecessary cast through `object` just to compile a standard WinForms API call.

Expected Behavior

DisplayFusion should compile standard WinForms code using `Graphics` and `TextRenderer` without requiring manual references or workarounds, regardless of whether a standalone .NET SDK is installed.

Questions

1. Is this a known issue with the DisplayFusion 12.1.x scripted function compiler?
2. Does DisplayFusion automatically include `System.Private.Windows.GdiPlus.dll` in its compilation references?
3. Is there a fix planned or already available in a beta release?

This appears similar to a .NET 10 reference resolution issue reported to Microsoft and fixed in .NET SDK 10.0.101:

https://github.com/dotnet/sdk/issues

Thanks!

DisplayFusion RSS: [DisplayFusion 12.1.1] C# Script Compilation Fails with CS0012 – Missing System.Private.Windows.GdiPlus Reference

RE: [DisplayFusion 12.1.1] C# Script Compilation Fails with CS0012 – Missing System.Private.Windows.GdiPlus Reference

[DisplayFusion 12.1.1] C# Script Compilation Fails with CS0012 – Missing System.Private.Windows.GdiPlus Reference

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