Entity Framework - lazy loading or additional async/await query method?

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I have these Domain Models

public class Topic
{
    public int TopicId { get; set; }

    public virtual ICollection<Post> Posts { get; set; }
}

public class Post
{
    public int PostId { get; set; }

    public int? TopicId { get; set; }
    public virtual Topic Topic { get; set; }
}

For example I would like to impliment method TestAsync, there I want to work with Topic object and related Posts objects.

Topic model I can get using async method and topicId as param.

public async Task<bool> TestAsync(int topicId)
{
    var topic = await topicService.GetByIdAsync(topicId);

    // posts ...
}

And I have two ways, how to get related posts. But, what the difference if I will use LazyLoading or just another async query?

// Example: 1 (LazyLoading)
var posts = topic.Posts;

// OR Example: 2 (Async method)
var posts = await postService.GetAllByTopicIdAsync(topicId);

So, I think that Example:1 will works synchronously, and also that I lose all the advantages of async/await code. But Example: 2 makes me think, that may be I dont know all charms of Lazy Loading:) Could anyone clarify what solution I should use and why? Thanks:)

async-await lazy-loading entity-framework asp.net c#
3 Answers
        public async Task<TProperty> GetReferenceAsync<TEntity, TProperty>(DBContext context, TEntity entity, Expression<Func<TEntity, TProperty>> property)
        where TEntity : class, IIdentifiable where TProperty : class
        {
            var getProperty = property.Compile();
            var value = getProperty(entity);
            if (value != null) { return value; }

            await context.Entry(entity).Reference(property).LoadAsync();
            return getProperty(entity);
        }

Usage: var posts = await GetReferenceAsync(context, topic, e => e.Posts);

user_730480
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