#MLNET – How to use the AutoML API in a Console App

Hi !

In my last posts I was testing AutoML using the Model Builder inside Visual Studio and also the CLI commands. There is also an API to use this in a .Net app, and the usage is very simple.

It all start, of course, adding the [Microsoft.ML.AutoML] nuget package

I read the documentation in [How to use the ML.NET automated machine learning API], and I created the following sample using the same data as in my previous posts.

private const uint ExperimentTime = 180;
static void Main(string[] args)
var mlContext = new MLContext();
Console.WriteLine("Process complete! Press any key to close the app.");
public static void Train(MLContext mlContext)
// STEP 1: Load the data
var trainData = mlContext.Data.LoadFromTextFile(path: "AgeRangeData03_AgeGenderLabelEncodedMoreData.csv",
columns: new[]
new TextLoader.Column("Age", DataKind.Single, 0),
new TextLoader.Column("Gender", DataKind.Single, 1)
new TextLoader.Column("Label", DataKind.Single, 2)
hasHeader: true,
separatorChar: ','
var progressHandler = new MulticlassExperimentProgressHandler();
ConsoleHelper.ConsoleWriteHeader("=============== Running AutoML experiment ===============");
Console.WriteLine($"Running AutoML multiclass classification experiment for {ExperimentTime} seconds…");
ExperimentResult<MulticlassClassificationMetrics> experimentResult = mlContext.Auto()
.Execute(trainData, "Label", progressHandler: progressHandler);
// Print top models found by AutoML
catch (Exception ex)

The final result displays the results for each one of the tests and showcase the top 3 ranked models. This time LightGBM Trainer is one more time the best trainer to choose.

There is a full set of samples in the Machine Learning .Net Samples repository. I’ve reused some classes from the Common folder.

The complete source code is available https://github.com/elbruno/Blog/tree/master/20190516%20MLNET%20AutoML%20API

Happy Coding!

Greetings @ Toronto

El Bruno


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