building-code

Building the WinForms Repository

Prerequisites

Windows is required for WinForms runtime scenarios, test execution, and Visual Studio workflows.
Linux is supported for command-line restore/build only; use build.sh instead of build.cmd / Restore.cmd.
Visual Studio 2022 (for IDE builds) — see WinForms.vsconfig for required workloads.
The repo-local .NET SDK (specified in global.json) is used automatically by build.cmd and Restore.cmd. You do not need a machine-wide SDK install for command-line builds.

1 Restore

Restoring downloads the repo-local SDK and all NuGet packages.

.\Restore.cmd

Under the hood this runs:

eng\common\Build.ps1 -NativeToolsOnMachine -restore

You can pass any extra Build.ps1 flags after Restore.cmd, e.g. .\Restore.cmd -configuration Release.

2 Full Solution Build (preferred)

.\build.cmd

This restores and builds Winforms.sln in Debug|Any CPU by default.

Under the hood this runs:

eng\common\Build.ps1 -NativeToolsOnMachine -restore -build -bl

Common flags

Flag	Short	Description
`-configuration <Debug\|Release>`	`-c`	Build configuration (default: `Debug`)
`-platform <x86\|x64\|Any CPU>`		Platform (default: `Any CPU`)
`-restore`	`-r`	Restore only
`-build`	`-b`	Build only (skip restore if already done)
`-rebuild`		Clean + build
`-clean`		Delete build artifacts
`-pack`		Create NuGet packages (`Microsoft.Private.Winforms`)
`-bl` / `-binaryLog`		Emit `artifacts\log\Debug\Build.binlog`
`-ci`		CI mode (stricter warnings, signing, etc.)
`-test`	`-t`	Build and run unit tests
`-integrationTest`		Build and run integration / functional tests

Examples

# Release build
.\build.cmd -configuration Release

# Build and run unit tests
.\build.cmd -test

# Create NuGet package
.\build.cmd -pack

3 Optimized Building a Single Project (fast inner-loop)

Prefer rebuilding just the project(s) with recent changes by using the standard dotnet build command, after at least one initial successful full restore (via .\Restore.cmd or .\build.cmd).

This is much faster than building the whole solution.

# Build a single src project
dotnet build src\System.Windows.Forms\System.Windows.Forms.csproj

# Build a single test project
dotnet build src\test\unit\System.Windows.Forms\System.Windows.Forms.Tests.csproj

# Release configuration
dotnet build src\System.Windows.Forms\System.Windows.Forms.csproj -c Release

Tip: The repo-local SDK must be on your PATH. Running .\start-code.cmd or .\start-vs.cmd prepends it automatically. From a plain terminal you can also run .\Restore.cmd first (it sets up the SDK).

4 Building from Visual Studio

Run .\Restore.cmd (one-time, or after SDK/package changes).
Run .\start-vs.cmd — opens Winforms.sln with the repo-local SDK on PATH.
Build normally (Ctrl+Shift+B).

5 Building from Visual Studio Code

(Optional) .\Restore.cmd
.\start-code.cmd — opens the workspace with the repo-local SDK on PATH.
Build from the integrated terminal: .\build.cmd or dotnet build <project>.

Build Outputs

Artifact	Location
Binaries	`artifacts\bin\<Project>\Debug\<tfm>\`
Logs	`artifacts\log\`
Binary log	`artifacts\log\Debug\Build.binlog`
Test results	`artifacts\TestResults\`
NuGet packages	`artifacts\packages\`

Use the MSBuild Structured Log Viewer to inspect .binlog files when troubleshooting build errors.

Troubleshooting

Most errors are compile errors — fix them as usual.
MSBuild task errors — inspect artifacts\log\Debug\Build.binlog.
SDK version mismatch — the repo pins its SDK in global.json; run .\Restore.cmd to ensure the correct SDK is available.
VS preview features — if using a non-Preview VS, enable Tools → Options → Environment → Preview Features → Use previews of the .NET SDK.