LearningModelSession Class

Definition

Namespace:

Windows.AI.MachineLearning

Used to evaluate machine learning models.

public ref class LearningModelSession sealed : IClosable

/// [Windows.Foundation.Metadata.Activatable(Windows.AI.MachineLearning.ILearningModelSessionFactory, 65536, "Windows.AI.MachineLearning.MachineLearningContract")]
/// [Windows.Foundation.Metadata.ContractVersion(Windows.AI.MachineLearning.MachineLearningContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
/// [Windows.Foundation.Metadata.Activatable(Windows.AI.MachineLearning.ILearningModelSessionFactory2, 131072, "Windows.AI.MachineLearning.MachineLearningContract")]
class LearningModelSession final : IClosable

[Windows.Foundation.Metadata.Activatable(typeof(Windows.AI.MachineLearning.ILearningModelSessionFactory), 65536, "Windows.AI.MachineLearning.MachineLearningContract")]
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.AI.MachineLearning.MachineLearningContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
[Windows.Foundation.Metadata.Activatable(typeof(Windows.AI.MachineLearning.ILearningModelSessionFactory2), 131072, "Windows.AI.MachineLearning.MachineLearningContract")]
public sealed class LearningModelSession : System.IDisposable

function LearningModelSession(model, deviceToRunOn, learningModelSessionOptions)

Public NotInheritable Class LearningModelSession
Implements IDisposable

Inheritance

Object Platform::Object IInspectable LearningModelSession

Attributes

ActivatableAttribute ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Implements

IClosable IDisposable

Windows requirements

Device family	Windows 10, version 1809 (introduced in 10.0.17763.0)
API contract	Windows.AI.MachineLearning.MachineLearningContract (introduced in v1.0)

Examples

The following example loads a model and creates an evaluation session with it.

private async Task LoadModelAsync(string _modelFileName)
{
    LearningModel _model;
    LearningModelSession _session;

    try
    {
        // Load and create the model
        var modelFile = 
            await StorageFile.GetFileFromApplicationUriAsync(new Uri($"ms-appx:///Assets/{_modelFileName}"));
        _model = await LearningModel.LoadFromStorageFileAsync(modelFile);

        // Create the evaluation session with the model
        _session = new LearningModelSession(_model);

    }
    catch (Exception ex)
    {
        StatusBlock.Text = $"error: {ex.Message}";
        _model = null;
    }
}

Remarks

Windows Server

To use this API on Windows Server, you must use Windows Server 2019 with Desktop Experience.

Thread safety

This API is thread-safe.

Version history

Windows version	SDK version	Value added
1903	18362	LearningModelSession(LearningModel,LearningModelDevice,LearningModelSessionOptions)

Constructors

LearningModelSession(LearningModel)	Creates a session using the default device.
LearningModelSession(LearningModel, LearningModelDevice)	Creates a session using the specified device.
LearningModelSession(LearningModel, LearningModelDevice, LearningModelSessionOptions)	Creates a session using the specified device and additional inference options.

Properties

Device	Returns the session's evaluation device.
EvaluationProperties	Set of properties that control model evaluation.
Model	Returns the trained machine learning model for this session.

Methods

Close()	Closes the current LearningModelSession.
Dispose()	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
Evaluate(LearningModelBinding, String)	Evaluate the machine learning model using the feature values bound in bindings.
EvaluateAsync(LearningModelBinding, String)	Asynchronously evaluate the machine learning model using the feature values already bound in bindings.
EvaluateFeatures(IMap<String,Object>, String)	Evaluate the machine learning model using the feature values in features.
EvaluateFeaturesAsync(IMap<String,Object>, String)	Asynchronously evaluate the machine learning model using the feature values in features.

See also

• Windows ML
• Windows ML samples (GitHub)