The correct way to validate JSON property

Question

What is the correct way to use advance property validation when deserializing JSON to Model? I am providing the MyClass as an example. I need to validate Name( required ) and Email( e-mail address validation ). I do find only [JsonProperty(Required = Required.Always)] to validate the required properties and nothing for e-mail validation. Unfortunately, Data Annotation validators can't be used from MVC for validation.

One idea which comes to my mind is to create custom ContractResolver and attach to deserializer where I could perform custom validation. Any other methods to consider?

public class MyClass
{
   [JsonProperty(Required = Required.Always)]
   public string Name { get; set; }
   public string Email { get; set; }
}

_dto = JsonConvert.DeserializeObject<MyClass>(content);

Answer 1

public class MyClass
{
   [JsonProperty("name", Required = Required.Always)]
   public string Name { get; set; }

   [JsonProperty("email", Required = Required.Always)]
   public string Email { get; set; }
}

To validate the email you'll have to apply your own regex check after you deserialize.

Answer 2

So I've had some time to test this, and as I suspected, MailAddress is deserialized to a much more complex json object than a simple address - which means that if you want to keep your json as is, you can't change the property type to MailAddress .

However, this doesn't mean you can't take advantage of the built in format validation it has in it's constructor, just not with auto-implemented properties.
If you change your class to this -

public class MyClass
{
    private string email;

   [JsonProperty(Required = Required.Always)]
   public string Name { get; set; }
   [JsonProperty(Required = Required.Always)]
   public string Email { 
       get
       {
           return email;
       }
       set
       {
           var address = new MailAddress(value); 
           email = value;
       }
   }
}

Whenever you try to deserialize a json that contains an invalid format email address (and in fact, whenever you try to set this property to a string that's not a valid email address), you'll get a FormatException :

System.FormatException: The specified string is not in the form required for an e-mail address.