OutWit.Common.Licensing.MVVM 1.0.0

OutWit.Common.Licensing.MVVM

The licence panel, minus the view.

Every property, command and enablement rule a licence screen needs, already computed — over OutWit.Common.Licensing.

No UI framework. Not Avalonia, not WPF, not Blazor, not MudBlazor. Bring your own view and bind it.

Install

dotnet add package OutWit.Common.Licensing.MVVM

Why a ViewModel and not a control

Licensing a product costs one options block, a thin view, and the enforcement points that are genuinely its own business logic. The gate is a handful of lines; the panel is a screen — eleven status arms, four operating modes, an expiry that escalates, a fingerprint to read to support, a request to export and a licence to paste. Written per product, the third one is where arms start going missing.

So the panel ships as a ViewModel. The view stays yours, because a desktop app, a CAD add-in and an admin page do not agree on what a screen looks like — and they do not need to.

Use it

var licensing = Licensing.Create(options => options
    .ForProduct("WitSweep", ThisAssembly.Version)
    .WithKeyRing(LicenseKeyRing.FromJson(EmbeddedRing()))
    .WithBinding(new LicenseBindingProviderMachine())
    .WithStore(new LicenseStoreFile(licenceDirectory))
    .WithDemo(TimeSpan.FromDays(30))
    .WithPeriodicReload(TimeSpan.FromHours(6)));

var gateway = new LicenseGatewayLocal(licensing);

Panel = new LicensePanelViewModel<ApplicationViewModel>(
    applicationVm,
    gateway,
    clipboard,      // optional seam
    files,          // optional seam
    dispatcher);    // REQUIRED wherever there is a UI thread — see below

Then bind. Mode, ModeText, Severity, StatusDetail, ExpiryText, Fingerprint, Grants, Warnings, Installed, PastedToken, and commands for refresh, install, uninstall, request, copy and file transfer.

Hold it; do not inherit from it. A service page derives from a component base and a desktop view model from its own application root — a panel that insisted on being either could serve only one of them.

The gateway is the joint

public interface ILicenseGateway
{
    event LicenseSnapshotEventHandler SnapshotChanged;
    LicenseSnapshot Current { get; }
    Task<LicenseSnapshot> RefreshAsync();
    Task<LicenseInstallOutcome> InstallAsync(string token);
    Task<bool> RemoveAsync(string licenseId);
    Task<LicenseRequest> CreateRequestAsync(string? contact = null, string? notes = null);
}

LicenseGatewayLocal wraps an in-process ILicenseService. A remote implementation puts the same panel in a browser, one round trip from a licence it must never hold: the panel never learns which it has.

The seams

The dispatcher is required wherever there is a UI thread, despite being optional in the signature. StateChanged is awaited by nobody: the runtime raises it from wherever its own re-evaluation finished, and every await inside the licensing core suppresses the synchronization context by design so a desktop host can block on its first evaluation without deadlocking. The snapshot therefore arrives on a thread-pool thread — after an ordinary install, not only when a periodic reload is on. Omit the dispatcher only where there is no UI thread to marshal onto.

What it deliberately does not do

It does not gate. Products refuse different things for different reasons, and a generic refusal tells a customer nothing about which axis they fell off. The enforcement point stays hand-written, where a reviewer can read it.

It does not draw. See above.

Licence

Apache-2.0.