Required property not found in json - json

Question

I'm trying to make a field mandatory before submitting to the server. For this I used the [Required] data annotation for the model validation. It work as expected for the string data types but not for a double.
For some reason it's not working for the double type property.
Here is the code that I have for the model:
public class ProductMetadata
{
[Required]
public string Barcode { get; set; }
[StringLength(50)]
[Required(AllowEmptyStrings = false, ErrorMessage="Please insert the product name!")]
public string Name { get; set; }
[Range(0, 5000)]
public double ShippingCostPerUnit { get; set; }
[Range(0, 10000)]
public int QuantityForFreeShipping { get; set; }
public Nullable<int> CategoryId { get; set; }
public bool IsDeleted { get; set; }
[Range(0, 1000000)]
[Required(ErrorMessage="Please provide a unit price for the product!")]
public double UnitPrice { get; set; }
}
The response body is a JSON response and for none of the required fields completed has the following content:
{
"Message":"The request is invalid.",
"ModelState":
{"product":["Required property 'UnitPrice' not found in JSON. Path '', line 1, position 33."],
"product.Barcode":["The Barcode field is required."],
"product.Name":["Please insert the product name!"]
}
}
I don't understand why is working fine for the Name and Barcode and not for UnitPrice.
Edit 1:
If I remove the [Required] attribute and I put the input for the UnitPrice -1 I receive the appropriate validation message, so why is not working for the Required attribute?
Edit 2: The request payload(also updated the ProductMetadata class):
{IsDelete: false, CategoryId: 1}
CategoryId: 1
IsDelete: false
Any help is appreciated! Thanks!

Answer 1

The fastest decision is to make Unit Price nullable
[Range(0, 1000000)]
[Required(ErrorMessage="Please provide a unit price for the product!")]
public double? UnitPrice { get; set; }
The problem is the field Unit Price is missing in json and JSON Formatter tries to deserialize double and receives exception before Required is executed.