Date model binding in ASP.NET Core

Question

I'm building one ASP.NET Core Web API and I've recently found one issue regarding the binding of DateTime values.

In truth I have one minimumDate and one maximumDate properties for filtering in a certain resource. These are part of one Filtering object which just gets populated on the controller by model binding.

The issue is that the request is sent like this:

minimumDate=2014-01-20T00:00:00.000Z&maximumDate=2014-03-21T00:00:00.000Z

and on the controller one gets when debuging:

MinimumDate = 19/01/2014 22:00:00
MaximumDate = 20/03/2014 21:00:00

This is clearly wrong. The expected was:

MinimumDate = 20/01/2014 00:00:00
MaximumDate = 21/03/2014 00:00:00

It is reducing one day in both the minimum and maximum dates and furthermore it is messing the time part.

I thought at first it had to do with culture and globalization, but this is already set in the Startup configure method as:

CultureInfo.DefaultThreadCurrentCulture = new CultureInfo("pt-BR");
CultureInfo.DefaultThreadCurrentUICulture = new CultureInfo("pt-BR"); 

so I doubt this to be the reason.

What am I doing wrong? How to get dates properly being sent to the API with model binding?

EDIT I managed to solve the issue by manualy parsing the datetime objects using:

filtering.MinimumDate = DateTime.Parse(this.Request.Query["minimumDate"], null, System.Globalization.DateTimeStyles.RoundtripKind);
filtering.MaximumDate = DateTime.Parse(this.Request.Query["maximumDate"], null, System.Globalization.DateTimeStyles.RoundtripKind);

In other words, bypassing the model binder. Still, I want to know: why model binding is presenting this strange behavior here?

Answer 1

To me it looks like the model binder which uses Json.net behind the scenes is converting your UTC time to local time for BRT (UTC-3) which is why you see the date and time change. You should be able to update your JsonSerializerSettings property as:

new JsonSerializerSettings
{
     .....
   DateTimeZoneHandling = DateTimeZoneHandling.Utc,
    .....
} 

That should take care of proper model binding in your case.