Question

例如，我写这样的代码

        bool hasCustomer = true;

        JObject j = JObject.FromObject(new
        {
            customer = hasCustomer? new
            {
                name = "mike",
                age = 48
            }:null
        });


        JObject c = (JObject)j["customer"];
        if (c != null)
            string name = (string) c["name"];

这很好用。

但是如果我设置hasCustomer = false;

       JObject c = (JObject)j["customer"];

将抛出System.InValidCastException：

       Unable to cast object of type 'Newtonsoft.Json.Linq.JValue' to type 'Newtonsoft.Json.Linq.JObject'.

由于JObject可以为空，我原本应该为JObject c赋予null。

那么，处理这样的事情的最佳方式是什么？

Answer 1

忽略null，似乎产生了正确的行为。

    bool hasCustomer = false ;

    JsonSerializer s = new JsonSerializer() {
        NullValueHandling = NullValueHandling.Ignore
    };
    JObject j = JObject.FromObject( new {
        customer = hasCustomer ? new {
            name = "mike" ,
            age = 48
        } : null
    }, s );


    JObject c = (JObject)j[ "customer" ];

Answer 2

JObject可以为空，但这并不意味着JObject可以抛出null。你可以试试这个：

JObject j = JObject.FromObject(new
        {
            customer = hasCustomer? new
            {
                name = "mike",
                age = 48
            }:new Object()
        });

Json.net linq to json将null转换为JObject抛出异常

2 个答案: