JsonConvert.SerializeObject使用非空DateTime属性进行分类？

Question

Background

I have some JSON which is deserialized to a Class which has DateTime properties.

Sometimes the corresponding elements of the JSON are null .

When you try to deserialize the JSON to the class an error is thrown because a plain old DateTime can't accept a null .

Easy but removes functionality

So the easiest resolution is to make the accepting properties of the class a nullable DateTime ( DateTime? ) but if you do that there's then a lot of DateTime methods you can no longer use on those properties.

Works but ... weird ?

So in looking for alternatives I have considered the following :

public class FooRelaxed
{
    [Required(ErrorMessage = "Please enter the id.")]
    public int? Id { get; set; }

    [Required(ErrorMessage = "Please enter the Start Date.")]
    public DateTime? StartDate { get; set; }

    [Required(ErrorMessage = "Please enter the End Date.")]
    public DateTime? EndDate { get; set; }

    public FooRelaxed() { }

    public FooRelaxed(
                  int? id,
                  DateTime? startdate,
                  DateTime? enddate)
    {
        this.Id = id;
        this.EndDate = enddate;
        this.StartDate = startdate;
    }
}
public class FooStrict 

    [Required(ErrorMessage = "Please enter the id.")]
    public int Id { get; set; }

    [Required(ErrorMessage = "Please enter the Start Date.")]
    public DateTime StartDate { get; set; }

    [Required(ErrorMessage = "Please enter the End Date.")]
    public DateTime EndDate { get; set; }

    public FooStrict() { }

    public FooStrict(FooRelaxed obj)
    {
        this.Id = Convert.ToInt32(obj.Id);
        this.EndDate = Convert.ToDateTime(obj.EndDate);
        this.StartDate = Convert.ToDateTime(obj.StartDate);
    }
}

I then use these classes to :

• Deserialize the JSON to the class FooRelaxed, which has nullable DateTime properties
• Validate the properties of the resulting object by calling Validator.TryValidateObject on it.
• Assuming there are no errors then instantiate the 'shadow' class, FooStrict, which has non-nullable DateTime properties using the FooRexlaxed instance as an arg to the constructor
• Use FooStrict for all subsequent processing

I'm sure there must be a better approach than this but I don't know what it is . Can anyone suggest a better solution ?

Answer 1

Decorate with appropriate JsonProperty attribute:

[JsonProperty(NullValueHandling=NullValueHandling.Ignore)]

Or

[JsonProperty("<NameOfProperty>", NullValueHandling=NullValueHandling.Ignore)]

Final code would be:

[JsonProperty("EndDate", NullValueHandling=NullValueHandling.Ignore)]
public DateTime EndDate { get; set; }

[JsonProperty("StartDate", NullValueHandling=NullValueHandling.Ignore)]
public DateTime StartDate { get; set; }