我有一个json文本，我想获取作者姓名和描述标签的值。不需要其他字段，如url和urltoimage等等。 当我运行以下代码时，不提供任何字符串值。我觉得有些错误在这里。
{
"status": "ok",
"articles": [
{
"source": {
"id": "techcrunch",
"name": "TechCrunch"
},
"author": "Khaled \"Tito\" Hamze",
"title": "Crunch Report",
"description": "Your daily roundup of the biggest TechCrunch stories and startup news.",
"url": "https://techcrunch.com/video/crunchreport/",
"urlToImage": "https://tctechcrunch2011.files.wordpress.com/2015/03/tccrshowogo.jpg?w=500&h=200&crop=1",
"publishedAt": "2017-12-11T20:20:09Z"
},
{
"source": {
"id": "techcrunch",
"name": "TechCrunch"
},
"author": "Sarah Perez",
"title": "Facebook is trying to make the Poke happen again",
"description": "Facebook's \"Poke\" feature has never really gone away, but now the social network is giving it a more prominent placement - and is even considering expanding..",
"url": "https://techcrunch.com/2017/12/11/facebook-is-trying-to-make-the-poke-happen-again/",
"urlToImage": "https://tctechcrunch2011.files.wordpress.com/2017/12/facebook-poke-icon.jpg",
"publishedAt": "2017-12-11T20:02:30Z"
},
{
"source": {
"id": "techcrunch",
"name": "TechCrunch"
},
"author": "Sarah Perez",
"title": "Amazon Alexa can now wake you up to music",
"description": "This fall, Amazon made a play to become your new alarm clock with the introduction of a combination smart speaker and clock called the Echo Spot. Today, the..",
"url": "https://techcrunch.com/2017/12/11/amazon-alexa-can-now-wake-you-up-to-music/",
"urlToImage": "https://tctechcrunch2011.files.wordpress.com/2017/09/amazon-event-9270069.jpg",
"publishedAt": "2017-12-11T17:22:30Z"
},
{
"source": {
"id": "techcrunch",
"name": "TechCrunch"
},
"author": "Ingrid Lunden, Katie Roof",
"title": "Apple confirms Shazam acquisition; Snap and Spotify also expressed interest",
"description": "After we broke the story last week that Apple was acquiring London-based music and image recognition service Shazam, Apple confirmed the news today. It is..",
"url": "https://techcrunch.com/2017/12/11/apple-shazam-deal/",
"urlToImage": "https://tctechcrunch2011.files.wordpress.com/2017/12/shazam-app-icon-ios.jpg",
"publishedAt": "2017-12-11T15:59:31Z"
}
]}
怎么弄这个？下面是我的代码，它根本没有工作
var data = (JObject)JsonConvert.DeserializeObject(myJSON);
string nameArticles= data["articles"].Value<string>();
MessageBox.Show(nameArticles);
public class Source
{
public string id { get; set; }
public string name { get; set; }
}
public class Article
{
public Source source { get; set; }
public string author { get; set; }
public string title { get; set; }
public string description { get; set; }
public string url { get; set; }
public string urlToImage { get; set; }
public DateTime publishedAt { get; set; }
}
Article art = new Article();
art = JsonConvert.DeserializeObject<Article>(myJSON);
MessageBox.Show(art.description.ToString());
上面的代码返回对象未设置为实例错误！
答案 0 :(得分：1)
假设您希望反序列化为具体类（根据您的问题中显示的第二种尝试方法），那么您需要一个包装类来保存整个对象，并反序列化。目前，您正在尝试将整个对象序列化为文章，但只有该对象的“articles”数组中的单个对象才会与Article类中的结构匹配。您试图在对象的错误级别执行操作，并且您忘记了文章是列表（数组）这一事实。
这样的事情：
public class JSONResponse
{
public string status { get; set; }
public List<Article> articles { get; set; }
}
和
JSONResponse response = JsonConvert.DeserializeObject<JSONResponse>(myJSON);
然后，您可以使用普通循环遍历response.articles列表并提取作者姓名和说明。
答案 1 :(得分：1)
data["articles"]可能是JArray而不是字符串。您需要迭代上述JObject中的每个JArray，并提取作者和描述值
var data = (JObject)JsonConvert.DeserializeObject(myJSON);
var articles = data["articles"].Children();
foreach (var article in articles)
{
var author = article["author"].Value<string>();
var description = article["author"].Value<string>();
Console.WriteLine($"Author: " + author + ", Description: " + description);
}
这可以帮助您开始使用您正在做的任何事情。
答案 2 :(得分：1)
如果您不想创建包装类，可以尝试下面的代码段。
var json = "Your JSON string";
dynamic stuff = JsonConvert.DeserializeObject(json);
string name = stuff.status;
var arr = stuff.articles;
foreach (var a in arr)
{
var authorName = a.author;
}
答案 3 :(得分：0)
你的Json在下面的课程
public class Source
{
public string id { get; set; }
public string name{get;set;}
}
public class Article
{
public Source source { get; set; }
public string author { get; set; }
public string title { get; set; }
public string description { get; set; }
public string url { get; set; }
public string urlToImage { get; set; }
public DateTime publishedAt { get; set; }
}
public class RootObject
{
public string status { get; set; }
public List<Article> articles { get; set; }
}
所以你通过以下方式反序列化..
var data = JsonConvert.DeserializeObject<RootObject>(myJSON);
nameArticles=data.articles.FirstOrDefault().description;
MessageBox.Show(nameArticles);
答案 4 :(得分：0)
样本json数据
string jsonString = "{\"displayName\":\"Alex Wu\",\"signInNames\":[{\"type\":\"emailAddress\",\"value\":\"AlexW@example.com\"},{\"type\":\"emailAddress\",\"value\":\"AlexW2@example.com\"}]}";
将json转换为jObject并使用名为selectToken（）的内置方法获取值
JObject jObject = JObject.Parse(jsonString);
string displayName = (string)jObject.SelectToken("displayName");
string type = (string)jObject.SelectToken("signInNames[0].type");
string value = (string)jObject.SelectToken("signInNames[0].value");
Console.WriteLine("{0}, {1}, {2}", displayName, type, value);
JArray signInNames = (JArray)jObject.SelectToken("signInNames");
foreach (JToken signInName in signInNames)
{
type = (string)signInName.SelectToken("type");
value = (string)signInName.SelectToken("value");
Console.WriteLine("{0}, {1}", type, value);
}
谢谢
答案 5 :(得分：-1)
答案 6 :(得分：-1)
请为您的JSON文件创建一个类，并为所有标记添加属性 然后编写如下代码：
public class exampleJson{
public string author {get;set;}
public string description {get;set;}
.....
}
var data = JsonConvert.DeserializeObject<exampleJson>(myJSON);
string authorName = data.author;
string descriptions = data.description ;