Load data / lookups within contructor.

NotifiableTask.cs

using System;
using System.ComponentModel;
using System.Threading.Tasks;

namespace MyNameSpace
{
    public sealed class NotifiableTask<TResult> : INotifyPropertyChanged
    {
        public NotifiableTask(Task<TResult> task)
        {
            Task = task;

            if (!task.IsCompleted)
            {
                var _ = ExecuteAsync(task);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public string ErrorMessage => InnerException?.Message;

        public string IsCompletedPropertyName => nameof(IsCompleted);

        public bool IsNotCompleted => !Task.IsCompleted;

        public bool IsSuccessfullyCompleted => Task.Status == TaskStatus.RanToCompletion;

        public Task<TResult> Task { get; }

        public AggregateException Exception => Task.Exception;

        public Exception InnerException => Exception?.InnerException;

        public bool IsCanceled => Task.IsCanceled;

        public bool IsCompleted => Task.IsCompleted;

        public bool IsFaulted => Task.IsFaulted;

        public TResult Result => (Task.Status == TaskStatus.RanToCompletion) ? Task.Result : default(TResult);

        public TaskStatus Status => Task.Status;

        private async Task ExecuteAsync(Task task)
        {
            try
            {
                await task;
            }
            catch
            {
                // Do not propagate exception directly back to main UI loop.
            }

            var propertyChanged = PropertyChanged;

            if (propertyChanged == null) return;

            propertyChanged(this, new PropertyChangedEventArgs(nameof(Status)));
            propertyChanged(this, new PropertyChangedEventArgs(nameof(IsCompleted)));
            propertyChanged(this, new PropertyChangedEventArgs(nameof(IsNotCompleted)));

            if (task.IsCanceled)
            {
                propertyChanged(this, new PropertyChangedEventArgs(nameof(IsCanceled)));
                
                return;
            }
            
            if (task.IsFaulted)
            {
                propertyChanged(this, new PropertyChangedEventArgs(nameof(IsFaulted)));
                propertyChanged(this, new PropertyChangedEventArgs(nameof(Exception)));
                propertyChanged(this, new PropertyChangedEventArgs(nameof(InnerException)));
                propertyChanged(this, new PropertyChangedEventArgs(nameof(ErrorMessage)));
                
                return;
            }
            
            propertyChanged(this, new PropertyChangedEventArgs(nameof(IsSuccessfullyCompleted)));
            propertyChanged(this, new PropertyChangedEventArgs(nameof(Result)));
        }
    }
}