Unable to return anonymous object through an IActionResult Endpoint

I have a problem when I try to return an anonymous object/DTO from an endpoint in my ASP .NET Core 6 Web-Api Project. I get an error that it cannot implicitly convert the type to an IActionResult. The code I use was suggested in this answer but unfortunately it doesn’t work out for me, I also tried using to map the anonymous object to an dto but that didn’t work either. Any help would be greatly appreciated, thanks in advance.

I also tried to return an Json(output) like suggested in the answer but, Json() I can’t specify a using for “Json”, I also tried to return an JsonResult(output) by modifying the return type of the endpoint but that didn’t work either.

This is the code I use:

[HttpGet]
public IActionResult GetAllEndpoints()
{
    var endpoints = _endpoinDataSources
    .SelectMany(es => es.Endpoints)
    .OfType<RouteEndpoint>();
    var output = endpoints.Select(
        e =>
        {
            var controller = e.Metadata
                .OfType<ControllerActionDescriptor>()
                .FirstOrDefault();
            var action = controller != null
                ? $"{controller.ControllerName}.{controller.ActionName}"
                : null;
            var controllerMethod = controller != null
                ? $"{controller.ControllerTypeInfo.FullName}:{controller.MethodInfo.Name}"
                : null;
            return new GetEndpointsDto
            {
                Method = e.Metadata.OfType<HttpMethodMetadata>().FirstOrDefault()?.HttpMethods?[0],
                Route = $"/{e.RoutePattern.RawText.TrimStart('/')}",
                Action = action,
                ControllerMethod = controllerMethod
            };
        }
    );

    return output;
}

I also injected the EndPointDataSource through the controller constructor:

public MyController(IEnumerable<EndpointDataSource> endpointSources)
{
    _endpoinDataSources = endpointSources;
}

>Solution :

You need to be more specific with return type:

[HttpGet]
public IActionResult<List<GetEndpointsDto>> GetAllEndpoints()
{
  ...
  return Ok(output.toList())
}