The JSON value could not be converted to System.Nullable`1[System.DateTime

Question

I have a model with a nullable DateTime property

public DateTime? DateOfBirth { get; set; }

when calling the API with the following value for the property

{       "Country": "US",
       "State": "New York",
       "Zip" : "123455",
       "dateOfBirth": "8/15/62"
}

This error is thrown by .net framework:

"errors": {
        "$.dateOfBirth": [
            "The JSON value could not be converted to System.Nullable`1[System.DateTime]. Path: $.dateOfBirth | LineNumber: 9 | BytePositionInLine: 33."
        ]

The parsing seem to work with other date formats like yyyy-mm-dd, but not for the format mentioned above in the example.

Answer 1

I deserialized it using Newtonsoft.Json and had no errors in the processe. I used this class

public class Root
{
    public string Country { get; set; }
    public string State { get; set; }
    public string Zip { get; set; }
    public DateTime? dateOfBirth { get; set; }
}

but my Windows CultureInfo("en-US"). if your culture info is different or are using another serializer and have a propblem I would just advice you to change DateTime type to string, and try to convert ToDateTime after deserialization.

DateTime format depends on regioanal culture in the Windows settings, so if datetime string format in US (as in your json) but you are in Europe, you will always get the error , so IMHO you better use this code, since you can select a culture of json, not Windows default.

public class Root
{
    public string Country { get; set; }
    public string State { get; set; }
    public string Zip { get; set; }

     [JsonProperty("dateOfBirth")]
    private string DateOfBirth { get; set; }
    
    [JsonIgnore]
    public DateTime? dateOfBirth
    {
        get { return DateTime.Parse(DateOfBirth, new CultureInfo("en-US")); }
    }
}