抛出了Newtonsoft.Json.JsonSerializationException - Xamarin

Question

I am working with live feeds on my app. After converting to Json and trying to display on my application is get this an exception thrown. I have looked at many answers relating to this issue but most answers are just the same as what i have in my code below? How can i resolve this problem?

Activity

{
    string result = new HTTPDataHandler().GetHTTPData(@params[0]);
    return result;
}

protected override void OnPostExecute(string result){
    RssObject data = JsonConvert.DeserializeObject<RssObject>(result);
    mDialog.Dismiss();
    DataAdapter adapter = new DataAdapter(data, mainActivity);
    mainActivity.rv.SetAdapter(adapter);
    adapter.NotifyDataSetChanged();
}

Model

public class Feed
{
    public string url { get; set; }
    public string title { get; set; }
    public string link { get; set; }
    public string author { get; set; }
    public string description { get; set; }
    public string image { get; set; }
}

public class Item
{
    public string title { get; set; }
    public string pubDate { get; set; }
    public string link { get; set; }
    public string guid { get; set; }
    public string author { get; set; }
    public string thumbnail { get; set; }
    public string description { get; set; }
    public string content { get; set; }
    public List<object> enclosure { get; set; }
    public List<string> categories { get; set; }
}

public class RssObject
{
    public string status { get; set; }
    public Feed feed { get; set; }
    public List<Item> items { get; set; }
}

error

Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[System.Object]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path 'items[0].enclosure.link', line 1, position 1142.

json

"status": "ok"
"feed": {
"url": "http://rss.nytimes.com/services/xml/rss/nyt/Technology.xml"
"title": "NYT > Technology"
"link": "https://www.nytimes.com/section/technology?partner=rss&emc=rss"
"author": ""
"description": ""
"image": "https://static01.nyt.com/images/misc/NYT_logo_rss_250x40.png"
}
"items": [
{
"title": "Uber Fires Executive Over Handling of Rape Investigation in India"
"pubDate": "2017-06-08 00:55:39"
"link": "https://www.nytimes.com/2017/06/07/technology/uber-fires-executive.html?partner=rss&emc=rss"
"guid": "https://www.nytimes.com/2017/06/07/technology/uber-fires-executive.html"
"author": "MIKE ISAAC"
"thumbnail": ""
"description": "The president of Uber’s Asia business was terminated after reporters questioned why he obtained medical records of a woman attacked by her Uber driver."
"content": "The president of Uber’s Asia business was terminated after reporters questioned why he obtained medical records of a woman attacked by her Uber driver."
"enclosure": {
"link": "https://static01.nyt.com/images/2017/06/08/business/08UBER1-sub/08UBER1-sub-moth.jpg"
}
"categories": [
"0": "Uber Technologies Inc"
"1": "Sex Crimes"
"2": "Ethics and Official Misconduct"
"3": "Alexander, Eric"
]
}

Answer 1

If I understood correctly, you're trying work on an RSS feed converted into json. As far as I remember, in XML the enclosure tag has three required attributes "url", "length", and "type". So first issue is the enclosure is ill-formatted.

Assuming that json is how you want it to be. In json, enclosure is an object, notice {} not an array [] . But in C# its declared as List<object> which usually represents an array in json. So you're trying to deserialize an object into an List<object> .

There are couple of ways you can resolve this. One, if you know the schema of enclosure, create a new class to represent the schema and use it as type (or List if its supposed to be an array) instead of List<object> . Two, if enclosure is not necessary, just remove the property in C# class, so it can be ignored on deserialization. If you need enclosure, but don't know what the schema could be, let us know, we'll spend few more cycles to find a solution for you.