How to return Linq query result from asynchronous method

Question

I am developing an API which fetches data from a database, i am using an Azure Function with Entity Framework. So far i can easily fetch data from one table without any issues, the problem starts when i try to combine multiple tables and return the results. My desired goal would be to return some information from the Person table combined with some information from the Profile Table. I am getting an error stating that it cannot implicitly convert the type even thought I have created a new type to set it as the return type of the function.

This is my database diagram:

Database Img

My Context class:

 public virtual DbSet<Profile> Profile { get; set; }
    public virtual DbSet<ProfileSocialMedia> ProfileSocialMedia { get; set; }
    public virtual DbSet<SocialMediaPlatform> SocialMediaPlatform { get; set; }

    public Task<List<Profile>> GetProfileList()
    {
        var profiles = Profile.ToListAsync();

        return profiles;
    }

My HttpTrigger:

 [FunctionName(nameof(GetProfiles))]
    public Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "get-profiles")]
        HttpRequest req,
        ILogger log) => _helper.HandleAsync(async () =>
    {

        var leaders = await _context.GetProfileList();

        return new OkObjectResult(leaders);

    });

I have tried the following code:

My Attempt:

 public Task<List<Profile>> GetProfileList()
    {
        var profiles = Person.Join(Profile, person => person.Id, profile => profile.PersonId,
            (person, profile) => new
            {
                person.Id,
                person.FirstName,
                person.LastName,
                profile.PreviousOccupation
            }).ToListAsync();
        return profiles;
    }

QKuba · Accepted Answer · 2020-05-15 15:02:19Z

2

Ok, so in order to achieve what i wanted to achieve i had to create a new instance of the type i wanted to return like so:

public Task<List<LeaderProfileModel>> GetProfileList()
    {

        var profiles = Person.Join(Profile, person => person.Id, profile => profile.PersonId,
                (person, profile) => new {person, profile})
            .Where(f => f.person.FirstName == "Name" && f.person.LastName == "Nastname")
            .Select(lpm => new LeaderProfileModel()
            {
                Id = lpm.person.Id,
                FirstName = lpm.person.FirstName,
                LastName = lpm.person.LastName,
                PreviousOccupation = lpm.profile.PreviousOccupation
            }).ToListAsync();

        return profiles;
    }

answered May 15, 2020 at 15:02

QKuba

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