Question

我的课程定义如下

public class HotelRoomResponse
{
    public string rateCode { get; set; }
    public string rateDescription { get; set; }
    public RoomType RoomType { get; set; }
    public string supplierType { get; set; }
    public int propertyId { get; set; }
    public BedTypes BedTypes { get; set; }
    public string smokingPreferences { get; set; }
    public int rateOccupancyPerRoom { get; set; }
    public int quotedOccupancy { get; set; }
    public int minGuestAge { get; set; }
    public RateInfos RateInfos { get; set; }
    public ValueAdds ValueAdds { get; set; }
    public string deepLink { get; set; }
    public RoomImages RoomImages  { get; set; }
} 


public class ValueAdd
{
    [JsonProperty(PropertyName = "@id")]
    public string id { get; set; }
    public string description { get; set; }
}

public class ValueAdds
{
    private string valueaddsize="0";
    [JsonProperty(PropertyName = "size")]
    [DefaultValue("0")]
    public string size
    {
        get
        {
            return !string.IsNullOrEmpty(valueaddsize)
                       ? valueaddsize
                       : ((DefaultValueAttribute)
                          (TypeDescriptor.GetProperties(this)["size"].Attributes[
                              typeof(DefaultValueAttribute)])).Value.ToString();
        }
        set { valueaddsize = value; }
    }
    [JsonConverter(typeof(ObjectToArrayConverter<ValueAdd>))]
    public List<ValueAdd> ValueAdd { get; set; } 
}


public class RoomImage
{
    //// private string useurl = "~/no-picture-available.jpg";
    // [DefaultValue("~/no-picture-available.jpg")]
    // public string url { get; set; }

    private string useurl="~/no-picture-available.jpg";
    [DefaultValue("~/no-picture-available.jpg")]
    public string url
    {
        get
        {
            return !string.IsNullOrWhiteSpace(useurl)
                       ? useurl
                       : ((DefaultValueAttribute)
                          (TypeDescriptor.GetProperties(this)["url"].Attributes[
                              typeof(DefaultValueAttribute)])).Value.ToString();
        }
        set { useurl = value; }
    }
}

public class RoomImages
{
    public string size { get; set; }
    public RoomImage RoomImage { get; set; }
}

在反序列化过程中，缺少一些参数，即每次有几家酒店会生成RoomImages和ValueAdds，而有些酒店则不会。{/ p>

我的问题不是在反序列化过程后发送Null，而是尝试设置默认值，但反序列化后不会反映这些值。如何将默认值设置为RoomImages值为“无图像网址”，将ValueAdds设置为“无值添加”？

Answer 1

Json.Net将忽略json中不存在的属性，但我想你会谈论案例2（下面）。然后使用NullValueHandling枚举即可。

//Case 1 (Json doesn't contain the property)
var image = JsonConvert.DeserializeObject<RoomImage>("{}");
Console.WriteLine(image.Url); //<-- ~/no-picture-available.jpg

//Case 2 (Property is explicitly set to null)
var settings = new JsonSerializerSettings() {NullValueHandling = NullValueHandling.Ignore };
image = JsonConvert.DeserializeObject<RoomImage>("{\"Url\":null}", settings);
Console.WriteLine(image.Url); //<-- ~/no-picture-available.jpg

public class RoomImage
{
    string _url = "~/no-picture-available.jpg";
    public string Url { get { return _url; } set { _url = value; } }
}

使用Newtonsoft.Json进行反序列化 - 将默认值分配给Null参数

1 个答案: