nVentimiglia nVentimiglia - 14 days ago 7
C# Question

ModelState is valid with null model

I have a Model object with a required attribute

public class ApiPing
{
[Required]
public DateTime ClientTime { get; set; }

public DateTime ServerTime { get; set; }
}


I have a Controller method that checks model state.

public IHttpActionResult Ping(ApiPing model)
{
if (!ModelState.IsValid)
return BadRequest(ModelState);

model.ServerTime = DateTime.UtcNow;

return Ok(model);
}


If I submit a submit a proper request (with a model) to the action method I get an correct value from ModeState.IsValid (true). However, when I submit an invalid request (without a model, so the model is null) I get an erroneous ModelState.IsValid (also true).

I could simply check if the model is null in my code, but that smells. Is this an intended 'feature' or a bug in ModelState validation? Am I doing something wrong ? Am I expecting too much ?

Answer

I had the same problem before and the answer is already available in a few forums and even here at SO: ModelState.IsValid even when it should not be?

You can also add a custom filter to validate (invalidate) missing fields and/or null values http://www.asp.net/web-api/overview/formats-and-model-binding/model-validation-in-aspnet-web-api

http://www.strathweb.com/2012/10/clean-up-your-web-api-controllers-with-model-validation-and-null-check-filters/