Modernize to .NET 8 + SQLite (fix Windows 11 Access/ACE-OLEDB errors)

[johnli125308250-design]

Why

On Windows 11 the app frequently fails because the Access DB is accessed via Microsoft.ACE.OLEDB.12.0, which needs the Access Database Engine redistributable and a matching bitness (x64 app vs 32-bit Office) — the common "provider is not registered" errors. .NET Framework 4.8 itself runs fine on Win11; the database driver is the root cause.

What

• Access -> embedded SQLite (varManager.sqlite): no driver install, no bitness issues. The VS typed-DataSet TableAdapters were reimplemented on System.Data.SQLite with the same public method signatures, so all Forms code is unchanged. The two Access saved queries (installedScenes, varsView) are recreated as SQLite views.
• .NET Framework 4.8 -> .NET 8 (net8.0-windows, SDK-style): varManager + DragNDrop ported; MMDLoader net6 -> net8. LoadScene is intentionally kept on .NET 3.5 (it is injected into VaM's Unity/Mono and must stay).
• Vendored DgvFilterPopup (CPOL, from farosch/DgvFilterPopup) — the original ..\DgvFilterPopup project reference was missing from the repo, so the solution could not build.
• One-time migration tool (Settings dialog, or varManager.exe --migrate) imports an existing varManager.mdb into SQLite via ACE OLEDB. Verified on a real ~358k-row DB in ~2.6s.
• .NET 8 behavior-diff fixes: Process.Start UseShellExecute=true; DpiUnaware to keep the original layout; virtual-list teardown crash on close; deterministic GDI bitmap disposal; cache folder resolved from the exe dir.
• UX: double-buffered grid scrolling, lifted the 500-row batch caps, single gate for the shared BackgroundWorker.

Full write-up & verification in MODERNIZATION.md. Built with the .NET 8 SDK only (no VS needed): dotnet build varManager.sln -c Release.

Notes

• This is a large change — happy to split it into smaller PRs (e.g. SQLite first, then the .NET 8 port) if you prefer.
• The repo currently has no LICENSE file — would you be OK clarifying the license / whether you are happy taking this upstream? I want to respect your intent. 🙏
• Thanks for varManager — it is a great tool, this just keeps it running cleanly on Win11.

[A-Sparowe]

Why

On Windows 11 the app frequently fails because the Access DB is accessed via Microsoft.ACE.OLEDB.12.0, which needs the Access Database Engine redistributable and a matching bitness (x64 app vs 32-bit Office) — the common "provider is not registered" errors. .NET Framework 4.8 itself runs fine on Win11; the database driver is the root cause.

What

• Access -> embedded SQLite (varManager.sqlite): no driver install, no bitness issues. The VS typed-DataSet TableAdapters were reimplemented on System.Data.SQLite with the same public method signatures, so all Forms code is unchanged. The two Access saved queries (installedScenes, varsView) are recreated as SQLite views.
• .NET Framework 4.8 -> .NET 8 (net8.0-windows, SDK-style): varManager + DragNDrop ported; MMDLoader net6 -> net8. LoadScene is intentionally kept on .NET 3.5 (it is injected into VaM's Unity/Mono and must stay).
• Vendored DgvFilterPopup (CPOL, from farosch/DgvFilterPopup) — the original ..\DgvFilterPopup project reference was missing from the repo, so the solution could not build.
• One-time migration tool (Settings dialog, or varManager.exe --migrate) imports an existing varManager.mdb into SQLite via ACE OLEDB. Verified on a real ~358k-row DB in ~2.6s.
• .NET 8 behavior-diff fixes: Process.Start UseShellExecute=true; DpiUnaware to keep the original layout; virtual-list teardown crash on close; deterministic GDI bitmap disposal; cache folder resolved from the exe dir.
• UX: double-buffered grid scrolling, lifted the 500-row batch caps, single gate for the shared BackgroundWorker.

Full write-up & verification in MODERNIZATION.md. Built with the .NET 8 SDK only (no VS needed): dotnet build varManager.sln -c Release.

Notes

• This is a large change — happy to split it into smaller PRs (e.g. SQLite first, then the .NET 8 port) if you prefer.
• The repo currently has no LICENSE file — would you be OK clarifying the license / whether you are happy taking this upstream? I want to respect your intent. 🙏
• Thanks for varManager — it is a great tool, this just keeps it running cleanly on Win11.

Has there been any progress with this? I can get the program to work after about 10+ minutes of opening, then crashing, then opening again until it actually loads lol. I've been using it for a few years now and the crashing on opening has only gotten worse and taken longer to actually work without crashing.