CsvInputFormatter throws exception for nullable reference types

[patzila]

The exception is thrown everytime csv data is received if the model it's trying to parse contains nullable reference types.

I have a model like this

public class Item
{
    public string ItemID { get; set; } = "";
    public string ItemNumber { get; set; } = "";
    public string? Description { get; set; }
    public int Active { get; set; }
    public float? Weight { get; set; }
}

sample CSV to parse

ItemID,ItemNumber,Description,Active,Weight
10002-18985,10002-18985,3M 5952,1,0

The exception thrown

System.InvalidCastException: Invalid cast from 'System.String' to 'System.Nullable`1[[System.Single, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]'.
   at System.Convert.DefaultToType(IConvertible value, Type targetType, IFormatProvider provider)
   at System.String.System.IConvertible.ToType(Type type, IFormatProvider provider)
   at System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider)
   at WebApiContrib.Core.Formatter.Csv.CsvInputFormatter.ReadStreamAsync(Type type, Stream stream)
   at WebApiContrib.Core.Formatter.Csv.CsvInputFormatter.ReadRequestBodyAsync(InputFormatterContext context)
   at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(ModelBindingContext bindingContext)
   at Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(ActionContext actionContext, IModelBinder modelBinder, IValueProvider valueProvider, ParameterDescriptor parameter, ModelMetadata metadata, Object value)
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerBinderDelegateProvider.<>c__DisplayClass0_0.<<CreateBinderDelegate>g__Bind|0>d.MoveNext()

Can support for nullable reference types be added?

[damienbod]

@patzila yes, this sounds like a good idea. Will see if I can add this, unless you would like to do a PR youself.

Greetings Damien

[patzila]

If you can take a crack at it first that would be great :)