How to use Async methods of in a queryable generic repository?

Question

In my OData controller, I am using the generic repository found here and can do the following:

[Queryable]
public Task<IQueryable<ContentType>> Get()
{
    var result = _repository.Query().GetAsync();

    return result;
}

As I would like to add some conditions to the query, such as UserId and use the UnitOfWork pattern,

I'm trying the following:

[Queryable]
public Task<IQueryable<ContentType>> Get()
{
    // mock
    var userId = 111;

    var unitOfWork = new Repository.UnitOfWork(_db);

    var result = unitOfWork.Repository<ContentType>().Query().Get()
        .Where(u => u.UserId == userId).Cast<ContentType>() // <-- how to access .GetAsync()

    return result;
}

I have tried the following (which works), but wondering if this is in fact the best way of accomplishing this?

[Queryable]
public async Task<IQueryable<ContentType>> Get()
{
    // mock
    var userId = 102;

    var unitOfWork = new Repository.UnitOfWork(_db);

    var result = unitOfWork.Repository<ContentType>().Query().Get()
        .Where(u => u.UserId == userId).Cast<ContentType>().AsQueryable();

    return await Task.Factory.StartNew(() => result);
}

-- Update --

Based on the discussion, I have removed the async portion of this and done the following:

   public IEnumerable<ContentType> Get(ODataQueryOptions<ContentType> options)
    {
        var unitOfWork = new Repository.UnitOfWork(_db);

        // mock
        var userId = 102;

        var contentTypes = options.ApplyTo(unitOfWork.Repository<ContentType>().Query().Get()
            .Where(u => u.UserId == userId)
            .OrderBy(c => c.Description))
            .Cast<ContentType>().ToList();

        return contentTypes;
    }

I'm not stuck on doing this async, and it doesn't seem like there is a direct way to .GetAsync() from IQueryable<TEntity> (as defined in IReqpositoryQuery.cs), but curious to know of a proper way of accomplishing this.

Answer 1

You need to use the Filter method of IRepositoryQuery rather than using Where:

[Queryable]
public Task<IQueryable<ContentType>> Get()
{
    // mock
    var userId = 111;

    var unitOfWork = new Repository.UnitOfWork(_db);

    return unitOfWork.Repository<ContentType>().Query()
        .Filter(u => u.UserId == userId)
        .GetAsync();
}