Sparse Packaging Sample (WPF)

A minimal WPF app that demonstrates the production sparse packaging workflow with the winapp CLI: grant package identity to an ordinary desktop .exe by shipping a tiny identity-only .msix and registering it against the app's install directory — without moving your binaries into an MSIX.

The window queries Windows.ApplicationModel.Package.Current and shows the package family name when identity is present, or "No package identity" when running unpackaged.

Full background and troubleshooting: Sparse Packaging Guide.

What's here

sparse-app/
├── sparse-app.csproj      # WPF project (references app.manifest as the SxS manifest)
├── App.xaml / .cs
├── MainWindow.xaml / .cs  # Displays package identity status
├── app.manifest           # Side-by-side manifest containing the <msix> identity element (XML mode)
├── appxmanifest.xml       # Pre-generated sparse manifest (AllowExternalContent, win32App)
├── Assets/                # Visual assets — deployed at the EXTERNAL location, not in the .msix
└── installer/setup.iss    # Inno Setup script: install app + register sparse MSIX

Prerequisites

• Windows 10, version 2004 (build 19041)+ — required for sparse packaging.
• .NET SDK (10.0+).
• winapp CLI — winget install Microsoft.WinApp --source winget.

Walkthrough

Run these from the sparse-app directory.

1. Build the app

dotnet build

2. Generate the sparse identity manifest (optional — one is checked in)

The repo ships a ready-made appxmanifest.xml. To regenerate it in place from the built exe (sparse init defaults to a sparse/ folder in the current directory, so pass --output-dir . to write next to the checked-in sample files instead):

winapp init --exe .\bin\Debug\net10.0-windows10.0.19041.0\sparse-app.exe --sparse --output-dir . --use-defaults --force

This skips SDK installation — sparse identity packages have no SDK dependencies. It only writes appxmanifest.xml and Assets/.

3. Generate a development certificate

winapp cert generate --publisher "CN=Sparse App Sample"

The certificate subject must match the manifest Publisher (CN=Sparse App Sample), so pass it explicitly as shown. Install/trust the cert for local testing (winapp cert install .\devcert.pfx, admin).

4. Pack the identity-only MSIX

winapp pack .\appxmanifest.xml --cert .\devcert.pfx

Produces SparseAppSample.identity.msix — just the manifest, no binaries or assets.

5. Embed identity into the exe

The checked-in app.manifest already contains the <msix> element (XML mode), so a normal dotnet build embeds it. To (re)generate it, or to embed directly into a built exe:

# XML mode — update the checked-in side-by-side manifest, then rebuild
winapp embed-identity .\app.manifest --manifest .\appxmanifest.xml
dotnet build

# — or — EXE mode: embed straight into an already-built exe
winapp embed-identity .\bin\Debug\net10.0-windows10.0.19041.0\sparse-app.exe --manifest .\appxmanifest.xml

6. Register the package (development)

Add-AppxPackage -Path .\SparseAppSample.identity.msix `
  -ExternalLocation (Resolve-Path .\bin\Debug\net10.0-windows10.0.19041.0)

7. Run and verify

.\bin\Debug\net10.0-windows10.0.19041.0\sparse-app.exe

The window should show "Running with package identity" and the package family name. If it shows "No package identity", re-check steps 5–6.

8. Clean up

Get-AppxPackage -Name SparseAppSample | Remove-AppxPackage

Asset handling

The .msix is identity-only. The images in Assets/ are resolved from the external location (the install directory) at runtime — they are not bundled into the MSIX. Your installer must deploy Assets/ alongside the app.

(Optional) Build the installer

The installer/setup.iss script produces a setup.exe that installs the app, copies the .msix, and registers the sparse package automatically — the full production flow.

# 1. Publish the app
dotnet publish -c Release -r win-x64 --self-contained false

# 2. Build the identity MSIX (signed)
winapp cert generate --publisher "CN=Sparse App Sample"
winapp pack .\appxmanifest.xml --cert .\devcert.pfx

# 3. Compile the installer (requires Inno Setup: https://jrsoftware.org/isdl.php)
& "${env:ProgramFiles(x86)}\Inno Setup 6\ISCC.exe" installer\setup.iss

The generated installer registers the package on install (Add-AppxPackage -ExternalLocation) and unregisters it on uninstall (Remove-AppxPackage).

Runtime prerequisite: because the app is published framework-dependent (--self-contained false), the target machine needs the .NET 10 Desktop Runtime (x64). The installer checks for it and warns before continuing if it's missing. To remove that dependency, publish self-contained instead (dotnet publish -c Release -r win-x64 --self-contained true).