c# - json在c#问题中读取

Question

我正在使用一个函数来读取 json 文件并将类列表返回到 UI。我的类(class)是

 public class UseCase
    {
        public string UseCaseId { get; set;}
        public string UseCaseDescription { get; set;}
    }

函数是这样的

 List<UseCase> usecaseList = new List<UseCase>();
ReadUsecaseContentFronJsonFile1();
         usecaseList = UseCaseList();

UseCaseList() 是

private List<UseCase> UseCaseList()
        {
            List<UseCase> usecaseList = new List<UseCase>();
            foreach (var value in deserializedData1.Values)
            {
                UseCase objUC = new UseCase();

                objUC.UseCaseId = value.UseCaseId;
                objUC.UseCaseDescription = value.UseCaseDescription;
                usecaseList.Add(objUC);
            }
            return usecaseList;//isSigRequired;
        }

private void ReadUsecaseContentFronJsonFile1()
        {
            deserializedData1 = ReadFromJsonFile1<Dictionary<string, UseCase>>();
        }

读取json文件的函数是这样的

 protected static T ReadFromJsonFile1<T>() where T : new()
        {
            TextReader JsonReader = null;
            try
            {
                var filePath = ConfigurationManager.AppSettings.Get("UsecaseListPath");
                if (File.Exists(filePath))
                {
                    JsonReader = new StreamReader(filePath);
                    var fileContents = JsonReader.ReadToEnd();
                    return JsonConvert.DeserializeObject<T>(fileContents);
                }
                else
                {
                    return new T();
                }
            }
            finally
            {
                if (JsonReader != null)
                    JsonReader.Close();
            }
        }

我没有在 (deserializedData1) 中获取 json 文件值。可能是什么问题？？

我的 json 文件是:

{

    "UseCases": {
        "UseCase": [{
            "UseCaseId": "CCS01",
            "UseCaseDescription": "Add Device to  CHF device log"
        }, {
            "UseCaseId": "CCS02",
            "UseCaseDescription": "Remove device from  CHF device log"
        }, {
            "UseCaseId": "CCS03",
            "UseCaseDescription": "Restore CHF Device  Log"
        }
}

Answer 1

查看JSON文档的开头:

{
    "UseCases": {
        "UseCase": [{

它说您有一个根对象，其中包含一个对象，该对象包含一个包含列表的对象；)或者更恰本地说:

1. 你有一个根对象
2. 根对象包含一个名为“UseCases”的字段，它是一个对象。
3. “UseCases”字段包含一个属性“UseCase”，它是一个集合

代码:

// For the root object which contains the "UseCases" field
public class RootObject
{
    public UseCasesContainer UseCases { get; set; }
}

// For the "UsesCases" field, the tricky thing is that 
// it's not a collection but an object
public class UseCasesContainer
{

    // ..which contains a collection field.
    public Collection<UsesCase> UsesCase { get; set; }
}

集合本身包含您指定的 UseCase 对象。

因此要反序列化它，您可以像这样使用 json.net:

var rootObject = JsonConvert.DeserializeObject<RootObject>(yourJson);

//don't be fooled by the property name, this is the collection
var allUseCases = rootObject.UseCases.UseCase; 

如果您的 JSON 只应包含用例，您可以创建一个没有字段的文档:

[
        {
            "UseCaseId": "CCS01",
            "UseCaseDescription": "Add Device to  CHF device log"
        }, {
            "UseCaseId": "CCS02",
            "UseCaseDescription": "Remove device from  CHF device log"
        }, {
            "UseCaseId": "CCS03",
            "UseCaseDescription": "Restore CHF Device  Log"
        }
]

.. 可以反序列化为:

var useCases = JsonConvert.DeserializeObject<IList<UseCase>>(json);