在json.net中重命名JProperty

Question

我有以下属性

{
"bad": 
{
"Login": "someLogin",
"Street": "someStreet",
"House": "1",
"Flat": "0",
"LastIndication": 
[
"230",
"236"
],
"CurrentIndication": 
[
"263",
"273"
],
"Photo": 
[
null,
null
]
}
}

例如，我如何将其从"坏"重命名为"好"。是的，我看到了Abi Bellamkonda 的扩展方法

public static class NewtonsoftExtensions
{
public static void Rename(this JToken token, string newName)
{
var parent = token.Parent;
if (parent == null)
throw new InvalidOperationException("The parent is missing.");
var newToken = new JProperty(newName, token);
parent.Replace(newToken);
}
}

但它得到了这个exeption

无法将Newtonsoft.Json.Linq.JProperty添加到Newtonsoft.Json.Linq.JProperty.

Answer 1

有些违反直觉的是，该扩展方法假设您传递给它的token是JProperty的值，而不是JProperty本身。据推测，这是为了使其易于与方括号语法一起使用：

JObject jo = JObject.Parse(json);
jo["bad"].Rename("good");

如果你有一个对属性的引用，如果你在属性的Value上这样调用它，你仍然可以使用这个扩展方法：

JObject jo = JObject.Parse(json);
JProperty prop = jo.Property("bad");
prop.Value.Rename("good");

然而，这使得代码看起来很混乱。最好改进扩展方法，使其在两种情况下都能工作：

public static void Rename(this JToken token, string newName)
{
if (token == null)
throw new ArgumentNullException("token", "Cannot rename a null token");
JProperty property;
if (token.Type == JTokenType.Property)
{
if (token.Parent == null)
throw new InvalidOperationException("Cannot rename a property with no parent");
property = (JProperty)token;
}
else
{
if (token.Parent == null || token.Parent.Type != JTokenType.Property)
throw new InvalidOperationException("This token's parent is not a JProperty; cannot rename");
property = (JProperty)token.Parent;
}
// Note: to avoid triggering a clone of the existing property's value,
// we need to save a reference to it and then null out property.Value
// before adding the value to the new JProperty.  
// Thanks to @dbc for the suggestion.
var existingValue = property.Value;
property.Value = null;
var newProperty = new JProperty(newName, existingValue);
property.Replace(newProperty);
}

然后你可以做：

JObject jo = JObject.Parse(json);
jo.Property("bad").Rename("good");  // works with property reference
jo["good"].Rename("better");        // also works with square bracket syntax

Fiddle：https://dotnetfiddle.net/RSIdfx