Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
444 views
in Technique[技术] by (71.8m points)

c# - Accessed JArray values with invalid key value: "fields". Array position index expected

I am using the guardian API to try and retrieve stories but keep receiving an exception. The string of json contains the below json, however I can't access the body using LINQ.

Here it is:

{
    "response":{
    "status":"ok",
    "userTier":"approved",
    "total":1,
    "startIndex":1,
    "pageSize":10,
    "currentPage":1,
    "pages":1,
    "orderBy":"newest",
    "results":[{
      "id":"sustainable-business/sustainable-finance-where-next-open-thread",
      "sectionId":"sustainable-business",
      "sectionName":"Guardian Sustainable Business",
      "webPublicationDate":"2014-02-13T13:27:00Z",
      "webTitle":"Where next for sustainable finance? - open thread",
      "webUrl":"http://www.theguardian.com/sustainable-business/sustainable-finance-where-next-open-thread",
      "apiUrl":"http://content.guardianapis.com/sustainable-business/sustainable-finance-where-next-open-thread",
      "fields":{
        "body":"<img src="http://hits.theguardian.com/b/ss/guardiangu-api/1/H.20.3/98867?ns=guardian&amp;pageName=Where+next+for+sustainable+finance%3F+-+open+thread+Article+2043222&amp;ch=Guardian+Sustainable+Business&amp;c2=461773&amp;c4=MIC%3A+Finance+%28GSB%29%2CMIC%3A+Guardian+Sustainable+Business%2CPRO%3A+Sustainability+%28Guardian+Professional%29&amp;c3=theguardian.com&amp;c6=Laura+Paddison&amp;c7=14-Feb-13&amp;c8=2043222&amp;c9=Article" width="1" height="1" />..."
      }
     }]
     }
}

I have tried every thing including this:

string story = (string)ja["response"]["results"]["fields"]["body"];

Update:

public partial class Story : PhoneApplicationPage
{
    string url;
    string jsonData;

    // Http used so the json can be retrived via the get async methods
    HttpClient webClient = new HttpClient();

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        if (NavigationContext.QueryString.ContainsKey("key"))
        {
            string encodedValue = NavigationContext.QueryString["key"];
            url = Uri.UnescapeDataString(encodedValue);
            textBox.Text = url;
            guardianPanorama();
        }
    }
    private async void guardianPanorama()
    {
        try
        {
            HttpResponseMessage Result = await webClient.GetAsync(url);

            // This takes the http response content and is turned into a string
            jsonData = await Result.Content.ReadAsStringAsync();
           
            JObject ja = JObject.Parse(jsonData);

            // This takes the current bitcoin price and formats it so there is the      correct amount of decimal places
            string story = (string)ja["response"]["results"]["fields"]["body"];

            // It then gets added to the textbox
            textBox.Text = story;
        }
        catch (Exception errors)
        {
            MessageBox.Show("There has been a error with the Guardian API");
            Console.WriteLine("An error occured:" + errors);
        }
    }
}

Exception:

System.ArgumentException: Accessed JArray values with invalid key value: "fields". Array position index expected.

at Newtonsoft.Json.Linq.JArray.get_Item(Object key)

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

If you replace

// This takes the current bitcoin price and formats it so there is the correct amount of decimal places
string story = (string)ja["response"]["results"]["fields"]["body"];

with

// This takes the current bitcoin price and formats it so there is the correct amount of decimal places
string story = (string)ja["response"]["results"][0]["fields"]["body"];

that should work for your example. Note the square bracket after results in the example you provided, that indicates an array that should be accounted for in your access code.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...