json.NET抛出InvalidCastException反序列化2D数组 [英] json.NET throwing an InvalidCastException deserializing a 2D array

问题描述

我正在尝试从json字符串反序列化double值的二维数组.以下代码复制了我的问题:

I'm attempting to deserialize a 2 dimensional array of double values from a json string. The following code replicates my problem:

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

// Here is the json string I'm deserializing:
string json = @"{
                    ""array2D"": [
                    [
                        1.2120107490162675, 
                        -0.05202334010360783, 
                        -0.9376574575207149
                    ], 
                    [
                        0.03548978958456018, 
                        1.322076093231865, 
                        -4.430964590987738
                    ], 
                    [
                        6.428633738739363e-05, 
                        -1.6407574756162617e-05, 
                        1.0
                    ]
                    ], 
                    ""y"": 180, 
                    ""x"": 94
                }";

// Here is how I deserialize the string:
JObject obj = JObject.Parse(json);

int x = obj.Value<int>("x");
int y = obj.Value<int>("y");

// PROBLEM: InvalidCastException occurs at this line:
double[,] array = obj.Value<double[,]>("array2D");

两个整数x和y具有期望值94和180.但是，当执行到达// PROBLEM行时，会发生以下异常:

The two integers, x and y, have the expected values 94 and 180. But when execution hits the // PROBLEM line, the following exception occurs:

An unhandled exception of type 
'System.InvalidCastException' 
occurred in Newtonsoft.Json.dll

Additional information: 
Cannot cast Newtonsoft.Json.Linq.JArray
to Newtonsoft.Json.Linq.JToken.

我应该如何使用json.NET以便不会发生此异常?

array的期望值应该清楚.

推荐答案

这有效:

JObject obj = JObject.Parse(json);
double[,] array = obj["array2D"].ToObject<double[,]>();

因为，按照@dbc，

差异似乎没有得到很好的记录. JToken.Value 基本上可以一个 Convert.ChangeType 基本类型，而 ToObject()实际上反序列化.

the difference doesn't seem well documented. JToken.Value basically does a Convert.ChangeType which is for primitive types, while ToObject() actually deserializes.

这篇关于json.NET抛出InvalidCastException反序列化2D数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！