Question

我正在从一个文件中读取Json，当我尝试使用Newtonsoft Json对其进行反序列化时，它返回null。我正在从http://json2csharp.com/构建JSON类。我不确定它为什么说null是因为它使用StreamReader时引入的特殊符号如\ n，\ r \ n等。请帮忙。

Json（我查看了JsonLint及其有效的json）

{
    "Machine Learning Functions": [{
        "Function": "JaccardDistance",
        "ArgCount": 2,
        "Arg1": "Point1",
        "Arg1Type": "Point",
        "Arg2": "Point2",
        "Arg2Type": "Point",
        "Return": "distance",
        "ReturnType": "Double"
    }],
    "Math Functions": [{
        "Function": "Cosine",
        "ArgCount": 2,
        "Arg1": "document1",
        "Arg1Type": "String",
        "Arg2": "document2",
        "Arg2Type": "String",
        "Return": "angle",
        "ReturnType": "Integer"
    }, {
        "Function": "SQRT",
        "ArgCount": 1,
        "Arg1": "SomeNumber",
        "Arg1Type": "Integer",
        "Return": "Number",
        "ReturnType": "Integer"
    }]

}

C＃代码（取自json2csharp）

 public class MachineLearningFunction
    {
        public string Function { get; set; }
        public int ArgCount { get; set; }
        public string Arg1 { get; set; }
        public string Arg1Type { get; set; }
        public string Arg2 { get; set; }
        public string Arg2Type { get; set; }
        public string Return { get; set; }
        public string ReturnType { get; set; }
    }

    public class MathFunction
    {
        public string Function { get; set; }
        public int ArgCount { get; set; }
        public string Arg1 { get; set; }
        public string Arg1Type { get; set; }
        public string Arg2 { get; set; }
        public string Arg2Type { get; set; }
        public string Return { get; set; }
        public string ReturnType { get; set; }
    }

    public class RootObject
    {
        public List<MachineLearningFunction> MachineLearningFunctions { get; set; }
        public List<MathFunction> MathFunctions { get; set; }
    }

这个json被存储到一个文件中，当我保持一个断点时，我通过引入一些特殊的字符，如\ n，\ r等来读取字符串，但是当我尝试反序列化时，断点显示为null迭代列表时我得到一个空引用异常。

 string json = string.Empty;
            using (StreamReader reader = new StreamReader(@"C:\Users\Nikh\OneDrive\Documents\Application/json.txt"))
            {
                json = reader.ReadToEnd();
            }
 ParseAndConstructJson(json);

public void ParseAndConstructJson(string json) //Using Newtonsoft json
        {
            RootObject obj = JsonConvert.DeserializeObject<RootObject>(json);
            foreach (var item in obj.MachineLearningFunctions)
            {
                MessageBox.Show(item.Function);
            }//DataGrid dg = new DataGrid();
}

Answer 1

您需要在JsonProperty中使用RootObject定义属性，以将它们映射到json文件。

public class RootObject
{
    [JsonProperty(PropertyName ="Machine Learning Functions")]
    public List<MachineLearningFunction> MachineLearningFunctions { get; set; }

    [JsonProperty(PropertyName ="Math Functions")]
    public List<MathFunction> MathFunctions { get; set; }
}

Answer 2

从以下位置删除空格： JSON文件中的“机器学习功能”和“数学函数”，它会反复地反序列化您的对象。

从文件中读取json并反序列化始终返回null

2 个答案: