I have a JObject and want to get any property or array element coming from a string expression.
I already know how to do it explicitly, like:
jObject["a"][0]["b");
But I would like to do something like: jObject("a[0].b");
The reason is that I am allowing the user to specify what to gather from the JSON object, rather than hardcoding the operation.
You can use SelectToken
string json = #"{a:[{b:1}]}";
var jobj = JObject.Parse(json);
var token = jobj.SelectToken("a[0].b");
Console.WriteLine(token);
I want to get all properties from json that StartsWith particular text
dynamic results = JsonConvert.DeserializeObject<dynamic>(json);
So now below is what i get in results
{"abc" : "Text", "abcde" : "Text2","prop" : "myprop"}
Is it possible to do something like
results.Where(x => x.StartsWith("abc"))
You could simply use results.GetType().GetProperties(), which will give you an array of properties present in the deserialized JSON object.
You could then iterate over that array to get the PropertyInfo objects whose Name starts with whatever string you want, and call GetValue() to obtain the properties' values of interest.
Or you simply don't deserialize at all, but parse the object and treat it as JSON:
var jObject = JObject.Parse(jsonString);
foreach (var rootProperty in jObject)
{
if (rootProperty.Key.StartsWith("whatever"))
{
var valueOfInterest = rootProperty.Value;
}
}
Simply retrieve the runtime-type of the result-object and query its properties using Type.GetProperties:
var type = results.GetType();
type.GetProperties().Where(x => x.Name.StartsWith("abc"));
EDIT: Because any method called on an instance of dynamic is dynamic as well, you have to cast the result of results.GetType into Type. Otherwise you´ll get a compiler-err stating that you can´t use an anonymous method on a dynamically bound operation.
var type = (Type)results.GetType();
I have an object HttpWebResponse which do a request a get results correctly.
I fetch the parameters this way:
using (StreamReader streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
string result = streamReader.ReadToEnd();
return result;
}
However, is there a way to fetch a parameter value by giving a property the name?
Something like
string token = streamReader.GetValue("token");
If the response is JSON, you can use JSON.NET to deserialize/parse the text into an object and then access properties of the object. You can make use of a dynamic object so you don't have to define a type for serialization with JsonConvert.DeserializeObject. For example:
dynamic o = JsonConvert.DeserializeObject(result);
var token = o.token;
Is it possible to return a dynamic object from a json deserialization using json.net? I would like to do something like this:
dynamic jsonResponse = JsonConvert.Deserialize(json);
Console.WriteLine(jsonResponse.message);
Json.NET allows us to do this:
dynamic d = JObject.Parse("{number:1000, str:'string', array: [1,2,3,4,5,6]}");
Console.WriteLine(d.number);
Console.WriteLine(d.str);
Console.WriteLine(d.array.Count);
Output:
1000
string
6
Documentation here: LINQ to JSON with Json.NET
See also JObject.Parse and JArray.Parse
As of Json.NET 4.0 Release 1, there is native dynamic support:
[Test]
public void DynamicDeserialization()
{
dynamic jsonResponse = JsonConvert.DeserializeObject("{\"message\":\"Hi\"}");
jsonResponse.Works = true;
Console.WriteLine(jsonResponse.message); // Hi
Console.WriteLine(jsonResponse.Works); // True
Console.WriteLine(JsonConvert.SerializeObject(jsonResponse)); // {"message":"Hi","Works":true}
Assert.That(jsonResponse, Is.InstanceOf<dynamic>());
Assert.That(jsonResponse, Is.TypeOf<JObject>());
}
And, of course, the best way to get the current version is via NuGet.
Updated (11/12/2014) to address comments:
This works perfectly fine. If you inspect the type in the debugger you will see that the value is, in fact, dynamic. The underlying type is a JObject. If you want to control the type (like specifying ExpandoObject, then do so.
If you just deserialize to dynamic you will get a JObject back. You can get what you want by using an ExpandoObject.
var converter = new ExpandoObjectConverter();
dynamic message = JsonConvert.DeserializeObject<ExpandoObject>(jsonString, converter);
I know this is old post but JsonConvert actually has a different method so it would be
var product = new { Name = "", Price = 0 };
var jsonResponse = JsonConvert.DeserializeAnonymousType(json, product);
Yes you can do it using the JsonConvert.DeserializeObject. To do that, just simple do:
dynamic jsonResponse = JsonConvert.DeserializeObject(json);
Console.WriteLine(jsonResponse["message"]);
Note: At the time I answered this question in 2010, there was no way to deserialize without some sort of type, this allowed you to deserialize without having go define the actual class and allowed an anonymous class to be used to do the deserialization.
You need to have some sort of type to deserialize to. You could do something along the lines of:
var product = new { Name = "", Price = 0 };
dynamic jsonResponse = JsonConvert.Deserialize(json, product.GetType());
My answer is based on a solution for .NET 4.0's build in JSON serializer. Link to deserialize to anonymous types is here:
http://blogs.msdn.com/b/alexghi/archive/2008/12/22/using-anonymous-types-to-deserialize-json-data.aspx
If you use JSON.NET with old version which didn't JObject.
This is another simple way to make a dynamic object from JSON:
https://github.com/chsword/jdynamic
NuGet Install
PM> Install-Package JDynamic
Support using string index to access member like:
dynamic json = new JDynamic("{a:{a:1}}");
Assert.AreEqual(1, json["a"]["a"]);
Test Case
And you can use this util as following :
Get the value directly
dynamic json = new JDynamic("1");
//json.Value
2.Get the member in the json object
dynamic json = new JDynamic("{a:'abc'}");
//json.a is a string "abc"
dynamic json = new JDynamic("{a:3.1416}");
//json.a is 3.1416m
dynamic json = new JDynamic("{a:1}");
//json.a is integer: 1
3.IEnumerable
dynamic json = new JDynamic("[1,2,3]");
/json.Length/json.Count is 3
//And you can use json[0]/ json[2] to get the elements
dynamic json = new JDynamic("{a:[1,2,3]}");
//json.a.Length /json.a.Count is 3.
//And you can use json.a[0]/ json.a[2] to get the elements
dynamic json = new JDynamic("[{b:1},{c:1}]");
//json.Length/json.Count is 2.
//And you can use the json[0].b/json[1].c to get the num.
Other
dynamic json = new JDynamic("{a:{a:1} }");
//json.a.a is 1.
Yes it is possible. I have been doing that all the while.
dynamic Obj = JsonConvert.DeserializeObject(<your json string>);
It is a bit trickier for non native type. Suppose inside your Obj, there is a ClassA, and ClassB objects. They are all converted to JObject. What you need to do is:
ClassA ObjA = Obj.ObjA.ToObject<ClassA>();
ClassB ObjB = Obj.ObjB.ToObject<ClassB>();
StreamReader qryTmpltStream = new StreamReader(tmpltPath + "templates.json");
JsonTextReader qryTmpltReader = new JsonTextReader(qryTmpltStream);
JsonSerializer qryTmpltSrlzr = new JsonSerializer();
object jsonObject = qryTmpltSrlzr.Deserialize(qryTmpltReader);
var tplts = JsonConvert.DeserializeObject<JSONRepClass>(jsonObject);
In above code I'm trying to read in a json file then deserialize it into a class. The problem is, this: JsonConvert.DeserializeObject wants a string, but the Deserailize method call before it returns an object.
I tried casting to string and ToString(), but no go.
Anyone see what I'm missing here?
Try this, just read the json file contents into a string and deserialize it using Json.Net
var jSonString = File.ReadAllText(tmpltPath + "templates.json");
var tplts = JsonConvert.DeserializeObject<JSONRepClass>(jsonString);
This is the simplest way to use JSON.net to turn a json string into a strongly typed class.
YourClass myclass = new YourClass();
JsonConvert.PopulateObject(yourstring,myclass);