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Port an existing Windows ML app to NuGet package (C++)

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In this tutorial, we’ll take an existing WinML desktop application and port it to use the redistributable NuGet package.

Prerequisites

  • A WinML application. If you are creating a new application, see Tutorial: Create a Windows Machine Learning Desktop application (C++)
  • Windows 8.1 or higher
  • Visual Studio 2019 (or Visual Studio 2017, version 15.7.4 or later)
  • Download the CppWinRT NuGet package

Add the NuGet Package to your project

In the Visual Studio project for your existing application, navigate to the the Solution explorer and select Manage NuGet Packages for Solution. Choose the Microsoft.AI.MachineLearning NuGet package. Ensure you're adding to the correct project, and press Install.

Next, build your solution again. The C++/WinRT toolkit will parse the new headers and metadata from the Microsoft.AI.MachineLearning NuGet package, avoiding confusion in the next step.

Include the new header

For best practices, you should add a control flag to enable your app to swithc back and forth between using in-box Windows ML and the NuGet package.

#ifdef USE_WINML_NUGET
#include “winrt/Microsoft.AI.MachineLearning.h” 
#endif

Change the namespace

Next, allow the Windows::AI::Machinelearning to switch over to the Microsoft::AI::MachineLearning namespace using a control flag. By making this change, your code will automatically use the NuGet package if applicable.

#ifdef USE_WINML_NUGET 

Using namespace Microsoft::AI::MachineLearning 

#else 

Using namespace Windows::AI::MachineLearning 

#endif

Change the Preprocessor Definitions

Now, right-click on the project in the Solution Explorer and select Properties. In the Properties window, choose the Preprocessor page. Edit the Preprocessor Definitions, and change it to USE_WINML_NUGET:_DEBUG.

Save Build Configurations

Right-click on the solution in the Solution Explorer and select Properties. In the Properties window, select Configuration Manager. Open the drop-down menu for Active solution configuration and choose <New...>. Enter the name of the new solution configuration and make sure Create new project configurations is checked. Now, preprocessor definitions can be saved in desired build configurations.

Build and run

Your application now successfully uses the WinML NuGet Package.