即使具有自定义验证属性，Asp.net Web.APi也会返回内置错误响应

Question

Hi I am trying to create create a consistent validation for my registration page.Here is the property I am having trouble with:

    [DateTimeValidation(ErrorMessageResourceType = typeof(EnValidationResources), ErrorMessageResourceName = "__LK_UserModel_BirthDate_Is_Required__")]
    public DateTime BirthDate { get; set; }

As I was testing I realized that even if I added my own validation attribute for DateTime :

public class DateTimeValidation: ValidationAttribute
{
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var dateTimeString = value.ToString();
        DateTime dateTimeParseResult;
        DateTime.TryParse(dateTimeString, out dateTimeParseResult);
        if (dateTimeParseResult.Equals(default(DateTime)))
        {
            return new ValidationResult(ErrorMessageString);
        }
        return null;
    }

}

If a user posts a null DateTime I still get back this response text:

"Cannot convert null value to System.DateTime. Path 'birthDate', line 1, position 17."

How can I make asp.net web.api to stop returning the built in error responses text?

Answer 1

Try:

[DateTimeValidation(ErrorMessageResourceType = typeof(EnValidationResources), ErrorMessageResourceName = "__LK_UserModel_BirthDate_Is_Required__")]
public DateTime? BirthDate { get; set; } //use nullable type.