C# how to deserialize my json file using Newtonsoft?

Question

Okay so I have looked all over and could not find an answer to how to do this.

Here is my json file

    {
        "item": {
            "icon": "icon.png",
            "icon_large": "icon_large.png",
            "id": 453,
            "type": "misc",
            "typeIcon": "icontype.png",
            "name": "Item name",
            "description": "item description",
            "current": {
                "trend": "neutral",
                "price": 174
            },
            "today": {
                "trend": "positive",
                "price": "+2"
            },
            "premium": "false"
            }
    }

I have tried this class as a way to deserialize it (I only need the item's name and price from the "current" tree)

    public class MyItem
    {
        public Dictionary<string, Item> item;     
    }
    public class Item
    {
        public string name;
        public Dictionary<string, Current> current;
    }
    public class Current
    {
        public string price;
    }

And this is being called from my main class

    private void buttonAddItemToWatcher_Click(object sender, EventArgs e)
    {
        string url = "link to json above;         
        string json = new WebClient().DownloadString(url);

        MyItem newItem = new MyItem();

        JsonConvert.PopulateObject(json, newItem);

    }

but I get this error

An unhandled exception of type 'Newtonsoft.Json.JsonSerializationException' >occurred in Newtonsoft.Json.dll

Additional information: Error converting value >"icon.png" to type 'RS_GrandExchangeWatcher.Item'. Path 'item.icon', line 1, position 95.

I am not quite understanding how I should set up my class in order to populate my MyItem class with the json I have provided

I prefer to use the deserializer with `Dictionary` type and strong type a property class if I only want certain elements out of it. — Paul Carlton, Oct 17 '16 at 23:49
Automatically creating types from json via tool like VS (http://stackoverflow.com/questions/18526659/how-to-show-the-paste-json-class-in-visual-studio-2012-when-clicking-on-paste/18527793#18527793) or http://json2csharp.com/ will make your life much easier. Code currently present in the post has no relation to JSON you trying to parse. — Alexei Levenkov, Oct 17 '16 at 23:55

trailmax · Accepted Answer · 2016-10-18T00:12:19.893

Your C# class does not match your JSON.

Copy your JSON, go to Visual Studio 2015, open a .cs file, in the menu Edit -> Paste Special -> Paste JSON as classes.

And you get corresponding C# classes:

public class MyItem
{
    public Item item { get; set; }
}

public class Item
{
    public string icon { get; set; }
    public string icon_large { get; set; }
    public int id { get; set; }
    public string type { get; set; }
    public string typeIcon { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public Current current { get; set; }
    public Today today { get; set; }
    public string premium { get; set; }
}

public class Current
{
    public string trend { get; set; }
    public int price { get; set; }
}

public class Today
{
    public string trend { get; set; }
    public string price { get; set; }
}

score 0 · Answer 2 · answered Oct 18 '16 at 00:01

Your schema does not match your JSON

Being MyItem your root object, it says that it has a property "item" with a value of type Dictionary<string, Item>, but your Item class has name and current properties only whereas in your JSON it has several others like "icon" and others.

You could try parsing everything as Dictionary<string, dynamic>, iterate and only parse the current property value to your Current class

C# how to deserialize my json file using Newtonsoft?

2 Answers2