Develop Reference

Deserialize arbitrary JSON keys and raw values

Using JSON.Net I want to deserialize a JSON object that looks something like this:
"properties": {
"foo": 1,
"bar": "Fred",
"baz": [694481.61, 693638.0, 692624.65, 692354.54]
}
and end up with a dictionary<string,string> that looks like this:
{ "foo", "1" },
{ "bar", "\"Fred\"" },
{ "baz", "[694481.61, 693638.0, 692624.65, 692354.54]" }
The key points to note are:
The keys are not known in advance. (Hence the use of a dictionary rather than deserializing to a class with predefined properties foo, bar and baz.)
The value strings in the dictionary are the raw JSON text from the JSON stream. So strings include their encapsulating quotation marks, and arrays include their encapsulating square brackets.
What I have tried so far
Parse the values as JRaw objects. This would work if I knew the key names in advance: I could declare matching properties in my class as type JRaw - e.g. public JRaw foo { get; set; }. But the key names are not predefined so I can't.
Create a RawValueDictionaryConverter : JsonConverter custom converter that takes the stream and deserializes it directly to a dictionary<string,string>. I thought this would be straightforward, but the raw text of the original stream is not available inside ReadJson(); the stream has already been tokenized and ReadJson() only receives the interpreted token and token type.
Write my own tokenizer and forget about using Json.NET. It may come to this but I don't want to 'reinvent the wheel.'

You can deserialise to Dictionary<string, JRaw> which gets you half way there. For example:
//Example class
public class Root
{
public Dictionary<string, JRaw> properties { get; set; }
}
var json = "<from the question>";
var result = JsonConvert.DeserializeObject<Root>(json);
foreach (var property in result.Properties)
{
var value = property.Value.ToString();
}
If you still want the values as strings, you can convert like this:
var stringDictionary = result.Properties.ToDictionary(p => p.Key, p => p.ToString());

Proper use of "$ref" property in JSON Pagination / Json.net

I'm trying to write a C# class for a RESTful web service which returns some items but uses JSON Pagination. I'm using JSON.net for serialization and deserialization.
I have the following code:
static void RefTest()
{
PageTest PageToTest = new PageTest();
PageToTest.next = new PageTest.PageLink();
PageToTest.next.reference = "https://www.example.com/RESTQuery/?page=1";
PageToTest.items = new List<string>();
PageToTest.items.Add("Car");
PageToTest.items.Add("Truck");
PageToTest.items.Add("Plane");
string JSON = JsonConvert.SerializeObject(PageToTest);
PageTest DeserializedPageTest = JsonConvert.DeserializeObject<PageTest>(JSON);
}
While the class looks as follows:
public class PageTest
{
public PageLink next;
public List<string> items;
public class PageLink
{
[JsonProperty("$ref")]
public string reference;
}
}
When I serialize that to a string, I get the expected result:
{
"next": {
"$ref":"https://www.example.com/RESTQuery/?page=1"
},
"items":
[
"Car",
"Truck",
"Plane"
]
}
Until now, everything works fine, it looks like json.net doesn't do anything special with the $ref property when serializing to a string.
Upon parsing of the string, however, json.net recognized the property named "$ref" as an reference to some id (which it can't find) and does NOT put it back on the deserialized object.
This is to be expected, but the web service is handing out pagination that way (With "next", "previous" and "last" attributes).
Basically, since it's impractical (I guess?) for the server to just give me all the values I will have to live with the pagination. So when I want to get all the items, I will have to deserialize the JSON response, check for additional items (indicated when there is a "next" property) and do the process again, until I have retrieved all the data I want.
Do you have any ideas on how I could handle that?
Thanks!

How do I deserialize this JSON?

How do I deserialize the following JSON with Web API (JSON.Net)?:
{
"action": "edit",
"table": "MainView",
"id": "row_1377",
"_group_id": "999",
"data": {
"ROTATION": "1", // This name/val can change
"EQUIPMENT": [{
"id": "6"
},
{
"id": "8"
}],
"NOTES": ""
}
}
The values in data represent columns and can change, so I can't make a set-in-stone object with e.g. a string named "NOTES" as in json.net deserialize string to nested class.
Notice EQUIPMENT contains multiple values. When it was previously just a "string:string" like NOTES, this JSON deserialized data into a Dictionary<string, string>, but now I need it to behave like its own dictionary. My last attempt was to deserialize into the following type:
public class EditorSubmissionJoined
{
public string _group_id { get; set; }
public string action { get; set; }
public string table { get; set; }
public string id { get; set; }
// "public" added below due to mistake noticed by Maggie Ying
public Dictionary<string, object> data { get; set; } // Trouble
}
I was hoping that the object could contain anything in data whether a KeyValuePair (like NOTES) or a dictionary (like EQUIPMENT).
I've also tried Dictionary<string, ICollection<Object>>, Object, and even ICollection<Dictionary<string, Object>>.
The problem is that my controller always gets EditorSubmissionJoined with nothing but null values:
public void Put(EditorSubmissionJoined ajaxSubmission) {
// ajaxSubmission has only NULL values
}

Try setting your 'data' property to public and your JSON should be able to model bind correctly.

There's a few ways you can do it. One way is to simply use a JObject and access the fields by name e.g. : jsonObject["data"]["ROTATION"]. You can "deserialize" that with JObject.Parse and just "parse" the JSON text into a JObject.
Alternatively you can write your own JsonConverter and tell JSON.net to use that converter when deserializing a specific type (e.g. JsonConverterAttribute). This requires parsing parts of the JSON text manually, in the ReadJson override, and really depends on what data you expect.
You can also use the dynamic approach that Preston commented on.
Which approach you pick depends on how strongly-typed you want things to be.

Deserializing JSON using C#

Finding some difficulty in sourcing information in trying to deserialize JSON in C#.
I have results from Google custom search returned in JSON format. I just want to check through my steps and establish the order in trying to deserialize it. Is this right?
I need to create classes to match
the JSON format. Kind of like a
creating schema file.
Use the JavaScriptSerializer() class and
deserialize method to extract the
relevant bits.
One of the issues I think I am going to run into is that I don't require all of the data returned but only the html links. How can I achieve that?
UPDATE
I have updated my question with the following JSON snippet and C# code. I want to output the string 'links' to console but it doesn't seem to be working. I think I am defining my classes wrongly?
JSON from Google Custom Search
handleResponse({
"kind": "customsearch#search",
"url": {
"type": "application/json",
"template": "https://www.googleapis.com/customsearch/v1?q\u003d{searchTerms}&num\u003d{count?}&start\u003d{startIndex?}&hr\u003d{language?}&safe\u003d{safe?}&cx\u003d{cx?}&cref\u003d{cref?}&sort\u003d{sort?}&alt\u003djson"
},
"queries": {
"nextPage": [
{
"title": "Google Custom Search - lectures",
"totalResults": 9590000,
"searchTerms": "lectures",
"count": 1,
"startIndex": 2,
"inputEncoding": "utf8",
"outputEncoding": "utf8",
"cx": "017576662512468239146:omuauf_lfve"
}
],
"request": [
{
"title": "Google Custom Search - lectures",
"totalResults": 9590000,
"searchTerms": "lectures",
"count": 1,
"startIndex": 1,
"inputEncoding": "utf8",
"outputEncoding": "utf8",
"cx": "017576662512468239146:omuauf_lfve"
}
]
},
"context": {
"title": "Curriculum",
"facets": [
[
{
"label": "lectures",
"anchor": "Lectures"
}
],
[
{
"label": "assignments",
"anchor": "Assignments"
}
],
[
{
"label": "reference",
"anchor": "Reference"
}
]
]
},
"items": [
{
"kind": "customsearch#result",
"title": "EE364a: Lecture Videos",
"htmlTitle": "EE364a: \u003cb\u003eLecture\u003c/b\u003e Videos",
"link": "http://www.stanford.edu/class/ee364a/videos.html",
"displayLink": "www.stanford.edu",
"snippet": "Apr 7, 2010 ... Course materials. Lecture slides · Lecture videos (2008) · Review sessions. Assignments. Homework · Reading. Exams. Final exam ...",
"htmlSnippet": "Apr 7, 2010 \u003cb\u003e...\u003c/b\u003e Course materials. \u003cb\u003eLecture\u003c/b\u003e slides · \u003cb\u003eLecture\u003c/b\u003e videos (2008) · Review sessions. \u003cbr\u003e Assignments. Homework · Reading. Exams. Final exam \u003cb\u003e...\u003c/b\u003e",
"cacheid": "TxVqFzFZLOsJ"
}
]
}
);
C# Snippet
public class GoogleSearchResults
{
public string link { get; set; }
}
public class Program
{
static void Main(string[] args)
{
//input search term
Console.WriteLine("What is your search query?:");
string searchTerm = Console.ReadLine();
//concantenate the strings using + symbol to make it URL friendly for google
string searchTermFormat = searchTerm.Replace(" ", "+");
//create a new instance of Webclient and use DownloadString method from the Webclient class to extract download html
WebClient client = new WebClient();
string Json = client.DownloadString("https://www.googleapis.com/customsearch/v1?key=My Key&cx=My CX&q=" + searchTermFormat);
//create a new instance of JavaScriptSerializer and deserialise the desired content
JavaScriptSerializer js = new JavaScriptSerializer();
GoogleSearchResults results = js.Deserialize<GoogleSearchResults>(Json);
Console.WriteLine(results);
//Console.WriteLine(htmlDoc);
Console.ReadLine();
}
}
Thanks

I use your #2 approach: deserialize with the JavaScriptSerializer.
This is what I do to deserialize a response from Facebook:
// get the id for the uploaded photo
var jss = new JavaScriptSerializer();
var resource = jss.Deserialize<Facebook.Data.Resource>(responseText);
....where Facebook.Data.Resource is defined like this:
namespace Facebook.Data
{
public class Resource
{
public string id { get; set; }
}
}
The responseText that I am deserializing from looks like this:
{"id":"10150111918987952",
"from":{"name":"Someone",
"id":"782272221"},
"name":"uploaded from Cropper. (at 12\/15\/2010 7:06:41 AM)",
"picture":"http:\/\/photos-f.ak.fbcdn.net\/hphotos-ak-snc4\/hs817.snc4\/69790_101501113333332_782377951_7551951_8193638_s.jpg",
...
But since I have only one property defined in the Resource class, I only deserialize that. Define the fields in your class that you want to deserialize.
It works to use inheritance, of course. You can define your data classes like this:
namespace Facebook.Data
{
public class Resource
{
public string id { get; set; }
}
public class Person : Resource
{
public string name { get; set; }
}
}
...and then you can deserialize a Person object.
EDIT
Ok, given the sample json you provided in the updated question, here's how I wrote the classes to hold the response:
public class GoogleSearchItem
{
public string kind { get; set; }
public string title { get; set; }
public string link { get; set; }
public string displayLink { get; set; }
// and so on... add more properties here if you want
// to deserialize them
}
public class SourceUrl
{
public string type { get; set; }
public string template { get; set; }
}
public class GoogleSearchResults
{
public string kind { get; set; }
public SourceUrl url { get; set; }
public GoogleSearchItem[] items { get; set; }
// and so on... add more properties here if you want to
// deserialize them
}
And here's the C# code to deserialize:
// create a new instance of JavaScriptSerializer
JavaScriptSerializer s1 = new JavaScriptSerializer();
// deserialise the received response
GoogleSearchResults results = s1.Deserialize<GoogleSearchResults>(json);
Console.WriteLine(s1.Serialize(results));
Some comments:
The toplevel class to hold the search result is called GoogleSearchResults.
The first property in the GoogleSearchResults class is kind, corresponding to the first named property in the json object. You had link which isn't going to work, because link is not the name of a top-level property in that json object. There are properties lower in the hierarchy of your json named "link" but JavaScriptSerializer won't pull out those lower level things into the higher level.
The next property in my GoogleSearchResults class is of type SourceUrl. This is because the url property in the json is not a simple string - it is a json object with two properties, each with a string value. So SourceUrl as a class in C# gets two string properties, each with the appropriate name to deserialize one of those named properties.
the next property in the GoogleSearchResults class is called "items" so that it can deserialize the items dictionary from your json. Now items, as the name suggests, is an array in the json, as denoted by the square bracket around its value. This means there can be more than one item, although in your case there is just one item. So this property in C# must be an array (or collection). Each item in the json result is not a simple string, so, once again, as we did with SourceUrl, we need to define a holder class to deserialize the item object: GoogleSearchItem. This class has a bunch of simple string properties. The properties in the C# class could also be of type int or some other type, if that's what the json requires.
finally, when printing out the result, if you just call Console.WriteLine(result) you will see the result of the ToString() method that is implicitly invoked by Console.WriteLine. This will merely print the name of the type, in this case is "GoogleSearchResults", which is not what you want, I think. In order to see what's in the object, you need to serialize it, as I've shown. In the output of that, you will see only the values of things you deserialized. Using the classes I provided, the result will have less information than the original, because I didn't provide properties in the C# class corresponding to some of the json properties, so those weren't deserialized.

You could take a look at Json.NET and its LINQ support to create and query JSON. By crafting a nice LINQ query you will get only the stuff you need (you can select, group by, count, min, max, whatever you like).

http://msdn.microsoft.com/en-us/library/bb412170.aspx
http://msdn.microsoft.com/en-us/library/bb410770.aspx
Pull out the property you need after you have converted the JSON representation to a type in your C# app. I don't think there's a way to extract only one property from the JSON representation before you have converted it (though I am not sure).

Deserialize Json in C#

{
"person": "david",
"images": {
"usable_sizes": [
[
[150,
41
],
"image1.png"
],
[
[220,
61
],
"image2.png"
],
[
[220,
61
],
"image3.png"
]
],
"uploader": null
}
}
I am using a JavaScriptSerializer in C# to parse some JSON. The above is the string I get back from the webrequest. Calling Deserialize on the string puts the Person in the right place in the object, but I don't know what type to use for the array nested under "images." I am at a complete loss.
here is relevant code:
TopLevelObject topObj = new JavaScriptSerialize().Deserialize<TopLevelObj>(jsonStream);
public TopLevelObject
{
public string person;
public imgStruct images;
}
public class imgStructure
{
public List<string[,][]> available_sizes;
}
but that's not taking. I have tried a variety of other forms for the class, but can't get the deserialize to put the data in without proper keys. I have no ability to change the inbound JSON as I am consuming it from a third party.

This is what I believe your classes should look like:
public class RootObj
{
public string person;
public ImageDataObj images;
}
public class ImageDataObj
{
public object uploader;
public List<List<object>> usable_sizes
}
As you can see the inner list is a list of objects. That is because the list has items of different types: one is a list (numerical data [150, 41]) and the other is a string (image name). I do not think you can strongly type the inner list for that reason.
Maybe it is worth examining on runtime (using the VS debugging tools) the structure of the objects inside the inner list and that could give you an indication of how to map it.
How the usable_images property type does look like if you take it to its detail is:
public List<List<Dictionary<List<int>,string>>> usable_sizes
but that is just a guess.

I would advise going to JSON.org and using one of their pre-built solutions.