I'm a bit confused with the Newtonsoft.Json JObject interface. Say I need to access the 'foo' property of the first child in my JSON object. My C# code:
string json = #"{
'someUnknownKey': { 'foo': 'bar' }
}";
JObject o = JObject.Parse(json);
JObject child = o.First.ToObject<JProperty>().Value.ToObject<JObject>();
string s = child["foo"].ToObject<string>();
This works, but is there a more elegant way to do it, without all the JProperty/JObject conversions?
EDIT: I would like to stress that the key name someUnknownKey is unknown so I can't use it in my code.
I believe you do need a conversion to indicate that you expect the first child token to be a property, but you can do it more simply than your current code:
string json = #"{
'someUnknownKey': { 'foo': 'bar' }
}";
JObject root = JObject.Parse(json);
Console.WriteLine(((JProperty) root.First).Value["foo"]);
Or to break it down slightly more clearly:
JObject root = JObject.Parse(json);
JProperty property = (JProperty) root.First;
Console.WriteLine(property.Value["foo"]);
Another option is to use the Properties() method to ask for the first property instead of the first child token. That way you don't need any conversion.
JObject root = JObject.Parse(json);
Console.WriteLine(root.Properties().First().Value["foo"]);
You can do something like this.
var jtk = o.Descendants().First().Children().First().Value<string>("foo")
You can query the json object as dynamic:
string json = #"{
'someUnknownKey': { 'foo': 'bar' }
}";
dynamic o = JArray.Parse(json);
string child = o.someUnknownKey.foo;
Look here for a reference https://www.newtonsoft.com/json/help/html/QueryJsonDynamic.htm
Alternatively you can use [] to access json properties:
JObject o = JObject.Parse(json);
string value = (string)(o['someUnknownKey']['foo']);
Related
I have to process the JSON object returned by an API response.
I tried by creating expando object and than adding all the properties to it.
and than copying the value to it.
dynamic dPropertyLinkValue = new ExpandoObject();
dPropertyLinkValue.link = "";
dPropertyLinkValue.value = "";
I am expecting a better way to do this, without expando object.
You can deserialize JSON by casting it to dynamic object. Please refer below sample:
Here deserializing Json to dynamic object and after that loop through its properties and in that you can check you value that whether it is object or not.
string jsonText = "{a:'testString',b:{'prop1':'value1'}}";
var jObj = JsonConvert.DeserializeObject<dynamic>(jsonText);
foreach (JProperty property in jObj)
{
string text = property.Name + " : " + property.Value;
//Here you can check whether property.Value is Jobject or any other value
}
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);
Can anyone tell me why I get an error when trying to output"dJson2.Type" in the code below?
string Json1= #"[{'Id':1, 'FirstName':'John', 'LastName':'Smith'}, {'Id':2, 'FirstName':'Jane', 'LastName':'Doe'}]";
dynamic dJson1= JsonConvert.DeserializeObject(Json1);
Console.WriteLine(dJson1.GetType());
Console.WriteLine(dJson1.Type);
string Json2 = #"{'Id':1, 'FirstName':'John', 'LastName':'Smith'}";
dynamic dJson2 = JsonConvert.DeserializeObject(Json2);
Console.WriteLine(dJson2.GetType());
Console.WriteLine(dJson2.Type);
The program dies on the Console.WriteLine(dJson2.Type) statement. The output of the program is...
Newtonsoft.Json.Linq.JArray
Array
Newtonsoft.Json.Linq.JObject
(should say Object here, I think)
Inspecting the local variables, dJson2 has a "Type" property with value "Object".
This is because JObject behaves similarly as System.Dynamic.ExpandoObject. Try to change your example to:
string Json2 = #"{'Id':1, 'FirstName':'John', 'LastName':'Smith'}";
dynamic dJson2 = JsonConvert.DeserializeObject(Json2);
dJson2.Type = "mynewfield";
Console.WriteLine(dJson2.GetType());
Console.WriteLine(dJson2.Type);
If you want to get property of underlying type you need to cast it (to JToken or JObject), otherwise requested property will be searched in
IDictionary<string, JToken> that JObject implements.
This example may help:
dynamic oobj = new JObject();
oobj.Type = "TEST";
Console.WriteLine(oobj.Type);
Console.WriteLine(((JObject)oobj).Type);
I've converted a XML into a JSON:
var json = JsonConvert.SerializeXmlNode(doc);
This is the result:
"author": {
"name": "Hey Guappo",
"yt:userId": "asfajgf346346fghsdgsWfiqcfr1pfQ"
}
and I'd like to access to the yt:userId.
I can't do this in .NET:
dynamic objectParsed = JObject.Parse(json);
var userID= (string)objectParsed.entry.author.yt:userId;
because of :. So how can I manage Namespace in JSON? I have:
var yt = XNamespace.Get("http://gdata.youtube.com/schemas/2007");
but I don't know how to apply it...
Try this:
JObject json = JObject.Parse(json);
string userId = json["author"]["yt:userId"].ToString();
This WILL work with the dynamic just fine. You don't have to use a JObject. In addition, I've highlighted the fact that you can use . notation UP TO your "yt:userId", at which point you need to index by string value.
dynamic objectParsed = JObject.Parse(json);
string userId = json.author["yt:userId"].ToString();
There is really no reason to NOT use a JObject, as Tobberoth pointed out, but there is also no technical restriction on using a dynamic if you prefer.
As a side note, avoid using an explicit cast to string with (string). Always use ToString().
This is the json string:
{"d":[{"numberOfRowsAdded":"26723"}]}
string json = DAO.getUploadDataSummary();
JObject uploadData = JObject.Parse(json);
string array = (string)uploadData.SelectToken("d");
How do I change the code to reader the values in 'numberOfRowsAdded?
JObject uploadData = JObject.Parse(json);
int rowsAdded = Convert.ToInt32((string)uploadData["d"][0]["numberOfRowsAdded"])
You need to cast to JArray:
string json = "{\"d\":[{\"numberOfRowsAdded\":\"26723\"}]}";
JObject parsed = JObject.Parse(json);
JArray array = (JArray) parsed["d"];
Console.WriteLine(array.Count);
You can cast your JObject as a dynamic object.
You can also cast your array to JArray object.
JObject yourObject;
//To access to the properties in "dot" notation use a dynamic object
dynamic obj = yourObject;
//Loop over the array
foreach (dynamic item in obj.d) {
var rows = (int)item.numberOfRowsAdded;
}
I played around with writing a generic method that can read any part of my json string. I tried a lot of the answers on this thread and it did not suit my need. So this is what I came up with. I use the following method in my service layer to read my configuration properties from the json string.
public T getValue<T>(string json,string jsonPropertyName)
{
var parsedResult= JObject.Parse(json);
return parsedResult.SelectToken(jsonPropertyName).ToObject<T>();
}
and this is how you would use it :
var result = service.getValue<List<string>>(json, "propertyName");
So you can use this to get specific properties within your json string and cast it to whatever you need it to be.