Iterating through JSON using System.Json

问题

I'm exploring the capabilities of .NET 4.5 System.Json library but there isn't much documentation, and it's quite tricky to search for due to the popular JSON.NET library.

I am wondering basically, how I'd loop through some JSON for example:

{ "People": { "Simon" : { Age: 25 }, "Steve" : { Age: 15 } } }

I have my JSON in a string, and I want to iterate through and display the ages of everyone.

So first I'd do:

var jsonObject = JsonObject.Parse(myString);

but then I'm at a loss of what to do next. I'm surprised that the parse method returns a JsonValue not a JsonObject.

What I want to do really is:

foreach (var child in jsonObject.Children)
{
  if (child.name == "People")
{
 // another foreach to loop over the people
 // get their name and age, eg. person.Name and person.Children.Age (LINQ this or something)

}

}

any ideas?

回答1:

Since the accepted answer does not helped me much because its one of the typcial useles "use this lib its better!" answers i figured that out.

Yes,

JsonObject.Parse(myJsonString);

Returns a JsonValue object that is the base class of all the Json* classes from System.Json. When you call JsonObject.Parse(..) then JsonValue.Parse() is really being called because of the inheritance.

to iterate over a JsonObject you can use:

var jsonObject = JsonValue.parse(jsonString);

foreach (KeyValuePair<string, JsonValue> value in jsonObject)
{
    Console.WriteLine("key:" + value.Key);
    Console.WriteLine("value:" + value.Value);
}

I dont tried out if this also works if its an JsonArray but maybe if its an JsonArray then you might want to do it with a classic for i:

for (var i = 0; i < jsonObject.Count; i++)
{
    Console.WriteLine("value:" + jsonObject[i]);
}

If you dont know if its an array or an object than you might check that before

if (jsonObject.GetType() == typeof JsonObject){
    //Iterate like an object 
}else if (jsonObject.GetType() == typeof JsonArray){
    //iterate like an array
}

回答2:

Using Json.Net and some Linq

string json = @"{ ""People"": { ""Simon"" : { Age: 25 }, ""Steve"" : { Age: 15 } } }";

var people =  JsonConvert.DeserializeObject<JObject>(json)["People"];

var dict = people.Children()
                 .Cast<JProperty>()
                 .ToDictionary(p => p.Name, p => p.Value["Age"]);

回答3:

for that kindly use json.net library its much better then the system.json itself

urclassobj = await JsonConvert.DeserializeObjectAsync<urclass>(json string)

then using foreach with linq on your list of objects

 foreach(var details in urclassobj
                        .Select((id) => new { id= id})
                        )
 {
   Console.WriteLine("{0}", details.id);
  }

and for object to json its

 string json2Send = await JsonConvert.SerializeObjectAsync(urclassobject);

来源：https://stackoverflow.com/questions/16338917/iterating-through-json-using-system-json

标签

json

.net-4.5