How to view tasks assigned to users

[Nokecy]

    public class MyUserTask : Activity
    {
        private readonly IContentSerializer _serializer;

        [ActivityInput(
            UIHint = ActivityInputUIHints.MultiText,
            Hint = "Provide a list of available actions",
            DefaultSyntax = SyntaxNames.Json,
            SupportedSyntaxes = new[] { SyntaxNames.Json, SyntaxNames.JavaScript, SyntaxNames.Liquid }
        )]
        public ICollection<string> Actions { get; set; } = new List<string>();

        [ActivityInput()]
        public string AssignUser { get; set; }

        [ActivityOutput] public string Output { get; set; }

        public MyUserTask(IContentSerializer serializer)
        {
            _serializer = serializer;
        }

        protected override bool OnCanExecute(ActivityExecutionContext context)
        {
            var userAction = GetUserAction(context);

            return Actions.Contains(userAction, StringComparer.OrdinalIgnoreCase);
        }

        protected override IActivityExecutionResult OnExecute(ActivityExecutionContext context) => Suspend();

        protected override IActivityExecutionResult OnResume(ActivityExecutionContext context)
        {
            var userAction = GetUserAction(context);
            Output = userAction;
            return Outcome(OutcomeNames.Done);
        }

        private static string GetUserAction(ActivityExecutionContext context) => (string)context.Input!;
    }

Everyone can see their own tasks

[sfmskywalker]

This is a great question and use case scenario that we haven't really defined yet. A couple of thoughts:

1. Since MyUserTask is a blocking activity, you will probably implement a bookmark provider for it. Your bookmark will contain the assigned user. This means that from your application, you can query the bookmark store (IBookmarkStore) to list all records with your bookmark type, and access the assigned user.
2. Although option 1 should be perfect, another option to consider might be for you to create a custom table that stores records of a workflow instance ID associated with the activity ID and assigned user. To populate this table, you would handle the WorkflowInstanceSaved event using a notification handler. From this handler, you check if the workflow instance is blocked on activities of type MyUserTask, and if so, you access its data to see what the assigned user is and create a record in your custom table. If not, then make sure to delete any and all records from your custom table with the workflow instance ID.
3. We might create an issue that raises a specific event called e.g. IndexWorkflowInstance to make it easy for applications to "know" when they might want to index the workflow instance into custom records of custom tables. This might help make implementing option 2 a little bit easier.

[Nokecy]

    public class WorkflowInstanceSavedTasks : INotificationHandler<WorkflowInstanceSaved>
    {
        private readonly IWorkflowInstanceStore _workflowInstanceStore;

        public WorkflowInstanceSavedTasks(IWorkflowInstanceStore workflowInstanceStore)
        {
            _workflowInstanceStore = workflowInstanceStore;
        }

        public Task Handle(WorkflowInstanceSaved notification, CancellationToken cancellationToken)
        {
            var correlationId = notification.WorkflowInstance.CorrelationId;
            var workflowInstanceId = notification.WorkflowInstance.Id;

            foreach (var blockingActivitie in notification.WorkflowInstance.BlockingActivities.Where(x => x.ActivityType == "MyUserTask"))
            {
                if (notification.WorkflowInstance.ActivityData.ContainsKey(blockingActivitie.ActivityId))
                {
                    var blockingActivitieData = notification.WorkflowInstance.ActivityData[blockingActivitie.ActivityId];

                    var assignUser = blockingActivitieData["AssignUser"]?.ToString();
                    var activityId = blockingActivitie.ActivityId;

                    //activity Name                ??
                    //activity DisplayName    ??
                    //activity Description       ??
                    //activity CreateTime       ??
                    //activity CompleteTime  ??
                }
            }

            return Task.CompletedTask;
        }
    }

like this ? how to get
//activity Name ??
//activity DisplayName ??
//activity Description ??
//activity CreateTime ??
//activity CompleteTime ??

[sfmskywalker]

To get activity name, display name and description, you need to access the workflow blueprint which contains activity blueprints.
To get the workflow blueprint, you need to inject IWorkflowRegistry. Then you can do something like this:

// Do this outside your foreach loop:
var workflowInstance = notification.WorkflowInstance;
var workflowBlueprint = await _workflowRegistry.GetAsync(workflowInstance.DefinitionId, null, VersionOptions.SpecificVersion(workflowInstance.Version), cancellationToken);

// Do this within the foreach loop:
var activityDescriptor = workflowBlueprint.Activities.First(x => x.Id == activityId);
var activityName = activityDescriptor.Name;
var activityDisplayName = activityDescriptor.DisplayName;
var activityDescription = activityDescriptor.Description;

I'm not sure about the activity created time. Do you mean: you want to know when the activity first executed?
If so, you probably could read from the IWorkflowExecutionLog service, where all activity execution is logged. Keep in mind that an activity can execute multiple times, so you need to order the results.

Example:

var specification = new WorkflowInstanceIdSpecification(workflowInstanceId).And(new ActivityIdSpecification(activityId));
var logEntries = await _workflowExecutionLog.FindEntryAsync(specification, cancellationToken);

// You now have zero or more events for a specific activity. Inspect the list using the debugger (or take a look at the database table or collection) to figure out how to determine the activity start and completion time.