LaunchDarkly Sample Client-Side .NET Applications

We've built a simple demo that demonstrates how LaunchDarkly's SDK works. Since the client-side .NET SDK can be used either on Xamarin-compatible mobile devices or in portable .NET code, there are three versions of the demo: a Xamarin Android app, a Xamarin iOS app, and a .NET Core console app.

Important: these demos are for the client-side .NET SDK, which is suitable for mobile or desktop applications. For server-side use, see https://github.com/launchdarkly/hello-dotnet-server.

Below, you'll find the basic build procedures, but for more comprehensive instructions, you can visit your Quickstart page or the client-side .NET SDK reference guide.

Instructions for Android and iOS

The Android and iOS demos require Visual Studio to build and run. For iOS, besides Visual Studio you must also have Xcode. You can run either on a real device or a simulator.

These demo apps use Android- and iOS-specific user interface components, rather than Xamarin Forms. The LaunchDarkly SDK in itself has no UI functionality, so in a Xamarin Forms app there would be no difference in how you would use the SDK.

1. Open LaunchDarkly.HelloDotNetClient.sln in Visual Studio.

2. Edit Shared/DemoParameters.cs and set the value of MobileKey to your LaunchDarkly SDK key. If there is an existing boolean feature flag in your LaunchDarkly project that you want to evaluate, set FeatureFlagKey to the flag key.

    public const string MobileKey = "1234567890abcdef";

    public const string FeatureFlagKey = "my-flag";

3. Build and run the XamarinAndroidApp or XamarinIOsApp project.

You should see the message "Feature flag '<flag key>' is <true/false> for this context".

If you leave the app running and use your LaunchDarkly dashboard to turn the flag off or on, you should see the message change to show the new value, showing how an app can receive live updates.

Instructions for .NET Core (console)

1. Edit Shared/DemoParameters as described above.

2. If you are using Visual Studio, open LaunchDarkly.HelloDotNetClient.sln and run the DotNetConsoleApp project. Or, to run from the command line, type the following command:

    dotnet run --project DotNetConsoleApp

You should see the message "Feature flag '<flag key>' is <true/false> for this context".

Unlike the Android and iOS demos, the console demo exits immediately, so it does not demonstrate receiving live updates of flags. However, the same streaming update functionality can be used in a long-running .NET Core application just as it would in a mobile app.