Building Qt Bridges C& module from source

Building the NuGet Package and Test Application (Windows, .NET 8)

This guide documents the steps used to:

1. Build a minimal Qt 6 from source (subset of modules)
2. Build the Qt.DotNet solution (adapter, generator, rules)
3. Pack a NuGet package
4. Build/Run the test application against the local package

Prerequisites

• Visual Studio 2022 (Desktop development with C++) with the x64 Native Tools Command Prompt
• .NET SDK 8+ (dotnet --version)
• Git
• CMake & ninja (installed with VS; available in the native tools prompt)
• Python & Perl (required by Qt build tooling) - see Qt's system requirements
• Sufficient disk space (Qt build can require tens of GB)

Build Qt 6 (subset) from source

Open x64 Native Tools Command Prompt for VS 2022 and run:

:: Choose a working directory
pushd D:\work

:: Create source/build/install folders
mkdir qt6-source
mkdir qt6-build
mkdir qt6-install

:: Clone Qt meta-repo (Qt6 uses the qt5 meta-repo name)
git clone git://code.qt.io/qt/qt5.git qt6-source

:: Initialize only the modules we need
cd qt6-source
init-repository --module-subset=qtbase,qtsvg,qtshadertools,qtdeclarative,qtquick3d,qtquick3dphysics,qtquicktimeline

:: Configure out-of-source build
cd ..\qt6-build
..\qt6-source\configure -prefix ..\qt6-install -release -opensource -confirm-license -submodules qtbase,qtsvg,qtshadertools,qtdeclarative,qtquick3d,qtquick3dphysics,qtquicktimeline -- -DQT_BUILD_TESTS=OFF -DQT_BUILD_EXAMPLES=OFF

:: Build and install
cmake --build .
cmake --install .

Notes

• You can add -D CMAKE_BUILD_PARALLEL_LEVEL=N to speed up builds (or use cmake --build . --parallel).
• If you run into generator issues, you can specify -G "Ninja" and install Ninja.
• The above turns off Qt tests/examples to keep the build lean.

Set Qt environment for the session

Use the same native tools prompt you used to build Qt:

set QtInstallRoot=D:\work\qt6-install

Build the Qt.DotNet solution

From the same prompt:

:: Go to your Qt.DotNet source checkout
pushd D:\work\qtdotnet

:: Restore and build (Release)
dotnet build -c Release

Build the test app as a smoke test:

:: Build the test app (adjust the path if different)
dotnet build -c Release examples\Primes\Primes.csproj

Test the package locally with the sample app

From the same prompt:

:: Build & run the sample app
dotnet run --project examples\Primes\Primes.csproj -c Release

Publish to nuget.org (optional)

:: Push the package
set NUGET_API_KEY=***your key***
dotnet nuget push nuget\local\*.nupkg --api-key %NUGET_API_KEY% --source https://api.nuget.org/v3/index.json

Troubleshooting

• MSVC/CMake not detected: Make sure you're using the x64 Native Tools prompt.
• Missing Python/Perl: Install them and ensure they're on PATH before running init-repository/configure.
• Long paths or spaces: Prefer short, space-free paths like D:\work.
• Rebuild from scratch: Delete the entire content of qt6-build and qt6-install directory and configure again.

What gets packaged

The NuGet contains:

• .NET adapter (host Qt/QML engine from C#)
• Generator (discovers your types and emits interop glue)
• Filtering rules (Include/Ignore/Exclude attributes)
• C++ include headers for the native bridge
• A minimal open-source Qt Quick runtime subset sufficient to run QML

All parts are versioned together to ensure compatibility.

Clean up

To revert environment changes, close the prompt or manually unset variables:

set QtInstallRoot=

After completing the steps above, you'll have:

• A locally built Qt install at %QtInstallRoot%
• A Release build of Qt.DotNet
• A NuGet package in nuget\local
• A test application built against that package