How to use Await with LINQ and DTO - asp.net

Question

I'm just getting to grips with creating a new WebAPI2 project in ASP.NET. I'm trying to get the controller to return data from a DTO I have created rather than the raw object classes that EF created. I've been following a tutorial on Microsoft Docs and have got my method which returns all records to work using the DTO, but I can't figure out how to correctly modify the method which only returns the record with the ID matching the passed parameter using an asynchronous task, like the default method does.
The default method generated by Visual Studio looks like this:
[ResponseType(typeof(Post))]
public async Task<IHttpActionResult> GetPost(int id)
{
Post post = await db.Post.FindAsync(id);
if (post == null)
{
return NotFound();
}
return Ok(post);
}
and I've got my modified method looking like this:
[ResponseType(typeof(PostDTO))]
public async Task<IHttpActionResult> GetPost(int id)
{
var _post = from p in db.Post
where p.PostID == id
select new PostDTO()
{
PostID = p.PostID,
SubmitTime = p.SubmitTime,
SubmitUsername = p.SubmitUsername,
};
if (_post == null)
{
return NotFound();
}
return Ok(_post);
}
This methods works just fine, but as you can see, it doesn't make use of .NET's Await/Async feature to perform the query asynchronously. I'll be honest and admit that I don't actually know if this matters, but I feel like if the default method was asynchronous, so should mine be. I just can't work out where to insert the Async and Await keywords to make this work.

Answer 1

You can use this method as,
[ResponseType(typeof(PostDTO))]
public async Task<IHttpActionResult> GetPost(int id)
{
var _post = await (from p in db.Post
where p.PostID == id
select new PostDTO()
{
PostID = p.PostID,
SubmitTime = p.SubmitTime,
SubmitUsername = p.SubmitUsername,
}).ToListAsync();
if (_post == null)
{
return NotFound();
}
return Ok(_post);
}