How to deserialize JSON to Dictionary<string, class>, where keys are unknown prior?

[Ryan Cole]

I'm using the latest version of RestSharp, from NuGet. I'm querying an API that returns a JSON dictionary in which the keys cannot be hard coded into a C# class before-hand. The keys are not known, coming from the API.

I'm following the recommended usage pattern outlined on the RestSharp Wiki here:https://github.com/restsharp/RestSharp/wiki/Recommended-Usage.

I tried calling Execute so that it looks like this: Execute>(request). This throws an error saying that it cannot convert a JSON array into that Dictionary, though. The exact exception is as follows ...

Unable to cast object of type 'RestSharp.JsonArray' to type
'System.Collections.Generic.IDictionary`2[System.String,System.Object]'.

And the HTTP response from the API looks like this ...

{
  "108" : {
    "name" : "Malzahar's Captains",
    "tier" : "SILVER",
    "queue" : "RANKED_SOLO_5x5"
  }
}

Any ideas?

[Brett Ryan]

Hi Ryan, when you try to deserialize are you specifying an object type of just `object` or are you giving a type? Or, are what you saying is that the value object for the dictionary has unknown keys?

There are two ways to deserialize a dictionary string. If you know the return type (Widget) then it can be achieved with the following:

    class Widget {
        public string ID {
            get;
            set;
        }
    }

    string inp = "{\"a\": {\"id\": \"1\"}, \"b\": {\"id\":\"2\"}}";
    Dictionary<string, Widget> res1 = SimpleJson.DeserializeObject<Dictionary<string, Widget>>(inp);

However, if the properties of `Widget` are not known at runtime you can deserialize the values to another dictionary:

    string inp = "{\"a\": {\"id\": \"1\"}, \"b\": {\"id\":\"2\"}}";
    Dictionary<string, Dictionary<string, object>> res
        = SimpleJson.DeserializeObject<Dictionary<string, Dictionary<string, object>>>(inp);

Note that I am using `SimpleJson` here directly for demonstration only.

[Ryan Cole]

Sorry about the ambiguity. No, I'm not explicitly specifying `object`, I'm specifying a POCO of mine, called `League`, for example. In most of these queries, the API returns a documented key-value format that I can easily (automatically with RestSharp) deserialize into my POCOs. For this one particular query though, it's returning a dictionary of string-to-League objects, where the string key is the name of the League. (League is a term used in this computer game) The League names are user created, and therefor will change based on whose data you're asking for. So, I can't map it to a POCO of mine, like the other queries.

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[Ryan Cole]

Sent last email before I was finished, Oops.

My scenario is like your first example. It's a string mapping to Widget, basically. I know the properties of Widget, I just don't know the string keys. I think I'm doing the equivalent of your SimpleJson line. My current code is visible on Github, with these specific lines highlighted here and here ...

https://github.com/ryancole/GlobalTaunt/blob/master/GlobalTaunt.Service/Services/BaseService.cs#L20

https://github.com/ryancole/GlobalTaunt/blob/master/GlobalTaunt.Service/Services/LeagueService.cs#L22

Thanks,

Ryan

[Ryan Cole]

Well, I can't figure it out. I'm trying to deserialize to Dictionary<String, Widget>, for example, and I'm not getting any errors. It's not parsing anything, though. Data is always null. I can see the JSON in the response, so the request went through just fine.

Ryan

[ThanosS]

{
  "108" : {
    "name" : "Malzahar's Captains",
    "tier" : "SILVER",
    "queue" : "RANKED_SOLO_5x5"
  }
}

You can use Json2C# which convert a json response to a data class. Here is the link : http://json2csharp.com/

When you type the json response you get, Json2C# say :

 

public class __invalid_type__108

{

    public string name { get; set; }

    public string tier { get; set; }

    public string queue { get; set; }

}

public class RootObject

{

    public __invalid_type__108 __invalid_name__108 { get; set; }

}

[Ryan Cole]

The result of JSON2C# contains a hard coded property name, though. This dictionary returned from the API cold conceivably have many other keys, as opposed to just "108". I think I need something along the lines of a more dynamic Dictionary<String, __invalid_type__108>, for example.

I've tried using a Dictionary<String, MyType> though and it fails to deserialize to it. The Data property is always null. Might this be a bug with RestSharp?

[Chintan Prajapati]

I am having same problem. 

Did anyone figureout solution ?

[Chintan Prajapati]

Finally i figured out how to correctly deserialize JSON to Dictionary<string, class>, where keys are unknown prior

I have blogged about it with example here . 

Hope it helps.

[Sam Bill]

Thanks, Chintan for sharing such a nice blog post. It was very useful for my website.