Json.net的LINQ to JSON投零到JObject拋出異常

Question

例如，我寫這樣的代碼

 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"]; 

這工作得很好。

但是，如果我設置hasCustomer = false;

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

將拋出System.InValidCastException：

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

我期待應該只分配null以JObject C，因爲C JObject可爲空。

那麼，處理這樣的事情的最佳方法是什麼？

Answer 1

忽略空，似乎產生正確的行爲。

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可以爲空，但這並不意味着JObject可以投射null。 你可以試試這個：

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