Receiving an event grid event

BuildController.cs

[HttpPost]
public IActionResult Post([FromBody]EventGridEvent[] value)
{
    if (value == null || value.Length != 1 || value[0].Data == null)
    {
        _logger.LogError("Bad event.");
        return BadRequest();
    }

    _logger.LogInformation($"Received event with type {value[0].EventType}");

    if (value[0].EventType == "Microsoft.EventGrid.SubscriptionValidationEvent")
    {
        var subscriptionValidation = value[0].Data.ToObject<SubscriptionValidationEvent>();
        _logger.LogInformation($"Validating subscription with token {subscriptionValidation.ValidationCode}");

        return Ok(new SubscriptionValidationResponse
        {
            ValidationResponse = subscriptionValidation.ValidationCode   
        });
    }

    _logger.LogInformation($"Parsing payload {value[0].Data}...");
    var msg = value[0].Data["message"].ToString();
    _logger.LogInformation($"Received message: {msg}");

    return Ok();
}