EF Core 5.x + OData 7.5.6 - $Top doesn't insert TOP inside of EF Query - entity-framework-core

Question

I'm thinking I missed something very simply but here is what I'm trying to todo. I have a .NET Core 5 project with EF Core 5 + OData 7.5.6. Everything appears to be working except for INSERT a TOP command in the generated SQL Query. Here is my controller. Very simple.
[EnableQuery]
[ApiController]
[Route("odata/[controller]")]
public class ConferenceHistoryController : ControllerBase
{
private readonly cdr_database_2Context _db;
public ConferenceHistoryController(cdr_database_2Context db)
{
_db = db;
}
[HttpGet]
public IEnumerable<_000701CallDataRecord> GetConferenceList()
{
// Return Full List
var query = _db._000701CallDataRecords;
var qs = query.ToQueryString();
return query.ToList();
}
}
When I send in my request to:
https://localhost:44355/odata/ConferenceHistory/?$select=RecordId,version&$top=5
The resulting SQL query is:
SELECT [0].[endDateTime], [0].[id], [0].[organizer], [0].[ParticipantCount], [0].[participants], [0].[PoorCall], [0].[type], [0].[version]
FROM [000701_CallDataRecord] AS [0]
As you can see, it's missing both the TOP and the SELECT commands. I have the following in my Startup.cs
public void ConfigureServices(IServiceCollection services)
{
// Add CORS to Project
services.AddCors(options =>
{
options.AddDefaultPolicy(builder => builder.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader());
});
// Add OData
services.AddOData();
services.AddControllers();
services.AddDbContext<cdr_database_2Context>(options =>
options.UseSqlServer(Configuration.GetConnectionString("CDRConnection"))
);
// Add Swagger Support
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "ODataAPI", Version = "v1" });
});
SetOutputFormatters(services);
}
And
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
// Use HTTPS & Routing
app.UseHttpsRedirection();
app.UseRouting();
// Auth???
app.UseAuthorization();
// Swagger Configure
app.UseSwagger();
app.UseSwaggerUI((config) =>
{
config.SwaggerEndpoint("/swagger/v1/swagger.json", "Swagger Odata Demo Api");
});
// Setup Endpoint for EDM
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.EnableDependencyInjection();
endpoints.Select().Expand().Filter().OrderBy().MaxTop(50).Count();
endpoints.MapODataRoute("odata", "odata", GetEdmModel());
});
}
And
private IEdmModel GetEdmModel()
{
// Add OData - EDM Definitions Below
var odataBuilder = new ODataConventionModelBuilder();
odataBuilder.EntitySet<WeatherForecast>("WeatherForecast");
odataBuilder.EntitySet<_000701CallDataRecord>("ConferenceHistory");
return odataBuilder.GetEdmModel();
}
Just looking for some direction on where I could have gone wrong. Everything else seems to be working really well.

Answer 1

Your controller needs to derive from ODataController not ControllerBase
You need to decorate GetConferenceList() with [Queryable]

Answer 2

OK, I figured out where the issue was in my above. It was with using the .ToList and the IEumerable. So if I changed this:
[HttpGet]
public IEnumerable<_000701CallDataRecord> GetConferenceList()
{
// Return Full List
var query = _db._000701CallDataRecords;
var qs = query.ToQueryString();
return query.ToList();
}
To:
[HttpGet]
public IEnumerable<_000701CallDataRecord> GetConferenceList()
{
// Return Full List
var query = _db._000701CallDataRecords;
var qs = query.ToQueryString();
return query;
}
It works. It's also worth noting that the .ToQueryString() doesn't show the OData/EF insertion of the TOP command. But if I enable .EnableSensitiveDataLogging() in the Startup.cs file, then I clearly see it being inserted into it.
Apparently, calling .ToList() will cause it to process and ignore any of the fancy OData commands. That was the only change and all was good then.