WorkflowInstancePreviewer.cs

public class WorkflowInstancePreviewer : IWorkflowInstancePreviewer
{
    private readonly IServiceScopeFactory _serviceScopeFactory;
    private readonly IWorkflowInstanceStore _workflowInstanceStore;
    private readonly IWorkflowRegistry _workflowRegistry;
    private readonly ICreatesActivityExecutionContextForActivityBlueprint _activityExecutionContextFactory;

    public WorkflowInstancePreviewer(IServiceScopeFactory serviceScopeFactory, IWorkflowInstanceStore workflowInstanceStore, IWorkflowRegistry workflowRegistry, ICreatesActivityExecutionContextForActivityBlueprint activityExecutionContextFactory)
    {
        _serviceScopeFactory = serviceScopeFactory;
        _workflowInstanceStore = workflowInstanceStore;
        _workflowRegistry = workflowRegistry;
        _activityExecutionContextFactory = activityExecutionContextFactory;
    }

    public async Task<WorkflowInstance> Get(WorkflowInstance workflowInstance, IWorkflowBlueprint workflowBlueprint)
    {
        var previewActivityData = new Dictionary<string, IDictionary<string, object?>>();

        using var scope = _serviceScopeFactory.CreateAsyncScope();
        var workflowExecutionContext = new WorkflowExecutionContext(scope.ServiceProvider, workflowBlueprint, workflowInstance);

        foreach (var workflowActivity in workflowBlueprint.Activities)
        {
            var currentActivityData = new Dictionary<string, object?>();

            previewActivityData.Add(workflowActivity.Id, currentActivityData);

            var activityExecutionContext = _activityExecutionContextFactory.CreateActivityExecutionContext(workflowActivity, workflowExecutionContext, CancellationToken.None);
            var activityPropertyProviders = workflowBlueprint.ActivityPropertyProviders.GetProviders(workflowActivity.Id);

            if (activityPropertyProviders == null) continue;

            foreach (var activityPropertyProvider in activityPropertyProviders)
            {
                var value = await activityPropertyProvider.Value.GetValueAsync(activityExecutionContext);
                currentActivityData.Add(activityPropertyProvider.Key, value);
            }
        }

        workflowInstance.ActivityData = previewActivityData;
        return workflowInstance;
    }
}