SamplesController.cs

[HttpGet("{id}")]
[ProducesResponseType(typeof(ServiceResponse), (int) HttpStatusCode.BadRequest)]
[ProducesResponseType(typeof(ServiceResponse), (int) HttpStatusCode.NotFound)]
[ProducesResponseType(typeof(ServiceResponse), (int) HttpStatusCode.OK)]
public async Task<IActionResult> Get(int id)
{
    if (id <= 0)
    {
        return BadRequest(Messages.InvalidRequest);
    }

    var query = new GetSampleByIdQuery(id);
    var sample = await Mediator.Send(query);
    if (sample.Data == null)
    {
        return NotFound(Messages.SampleNotFound);
    }
    
    return Ok(sample);
}