CODEWITHSUNDEEP
c#jsonjson.netjsonpath
Ashish Narmen
Ashish Narmen

Reputation: 876

Parse JSON using Newtonsoft.Json.Linq.JToken.SelectToken

I am trying to parse JSON to obtain the value of the VIN number in the following snippet. The SelectToken call is returning a null value. I tried using the same token to test on the following websites and it works there

I am unable to identify what is going on here. Is it because this token is not supported in Newtownsoft.Json, or is it something else

    [Test]
    public void Test()
    {
        string responseContent =
            "{\"GetAdvisorWipDetailPageResponse\":{\"AdvisorDetailPage\":{\"TaxLabel\":\"VAT\",\"Currency\":{\"Code\":\"UKL\",\"Description\":\"Sterling\",\"Symbol\":\"£\",\"Precision\":\"2\"},\"LastMileage\":\"0\",\"NetAmount\":\"52.73\",\"VATAmount\":\"10.55\",\"TotalAmount\":\"63.28\",\"VATRate\":\"20.00\",\"RTSLabourRate\":\"55.50\",\"DateOut\":\"2017-09-06\",\"TimeOut\":\"16:00\",\"CustomerName\":\"S 4133166Portor\",\"CustomerDetails\":{\"Name\":\"S 4133166Portor\",\"Address\":\"1 Alvin Street\\\\nHungerford\\\\n\\\\n\\\\n\"},\"ListSection\":[{\"Type\":\"2\",\"SectionDesc\":\"Vehicle Details\",\"Cols\":\"2\",\"DisplayRows\":\"10\",\"Rows\":\"10\",\"ListRow\":[{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Registration:\",\"Col2\":\"PRA4133166\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"VIN:\",\"Col2\":\"4133166\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Make:\",\"Col2\":\"Citroen\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Model:\",\"Col2\":\"C3 Picasso\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Colour:\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Fuel Type:\",\"Col2\":\"Petrol\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Last known odometer:\",\"Col2\":\"0\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Next service due:\",\"Col2\":\"1200 or 06/07/2018\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Registration date:\",\"Col2\":\"06/09/2017\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"MOT due date:\",\"Col2\":\"06/07/2018\"}}],\"Variant\":{\"Class\":\"CAR\",\"Desc\":\"Car\",\"Variants\":{\"Variant\":[{\"Class\":\"BIKE\",\"Desc\":\"Motorcycle\"},{\"Class\":\"CAR\",\"Desc\":\"Car\"},{\"Class\":\"COMP\",\"Desc\":\"Component vehicle\"},{\"Class\":\"HGV\",\"Desc\":\"Heavy Goods Vehicle\"},{\"Class\":\"LCV\",\"Desc\":\"Light Commercial Vehicle\"}]}}},{\"Type\":\"2\",\"SectionDesc\":\"Today's Service Details\",\"Cols\":\"2\",\"DisplayRows\":\"6\",\"Rows\":\"6\",\"ListRow\":[{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Repair number:\",\"Col2\":\"20285\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Account:\",\"Col2\":\"C0002 - Service Retail Cash Sales\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Notes:\",\"Col2\":\"Carry out repair :-\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Goods value:\",\"Col2\":\"£52.73\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"VAT value:\",\"Col2\":\"£10.55\"}},{\"WipNo\":\"20285\",\"Row\":{\"Col1\":\"Total value:\",\"Col2\":\"£63.28\"}}]},{\"Type\":\"4\",\"SectionDesc\":\"Recent Service History\"}],\"VHCCompleted\":\"0\",\"Reminders\":\"0\",\"PreviousVHC\":{\"Available\":\"0\"}},\"Version\":\"3.228\",\"Partition\":\"972\",\"Startup\":\"2017-09-06T15:40\",\"RequestsServiced\":\"1\"}}";
        string key = "GetAdvisorWipDetailPageResponse.AdvisorDetailPage.ListSection[0].ListRow[*].[?(@.Col1=='VIN:')].Col2";
        var content = JObject.Parse(responseContent);
        var value = content.SelectToken(key).ToString();
    }

The un-escaped string is here 

{"GetAdvisorWipDetailPageResponse":{"AdvisorDetailPage":{"TaxLabel":"VAT","Currency":{"Code":"UKL","Description":"Sterling","Symbol":"£","Precision":"2"},"LastMileage":"0","NetAmount":"52.73","VATAmount":"10.55","TotalAmount":"63.28","VATRate":"20.00","RTSLabourRate":"55.50","DateOut":"2017-09-06","TimeOut":"16:00","CustomerName":"S 4133166Portor","CustomerDetails":{"Name":"S 4133166Portor","Address":"1 Alvin Street\\nHungerford\\n\\n\\n"},"ListSection":[{"Type":"2","SectionDesc":"Vehicle Details","Cols":"2","DisplayRows":"10","Rows":"10","ListRow":[{"WipNo":"20285","Row":{"Col1":"Registration:","Col2":"PRA4133166"}},{"WipNo":"20285","Row":{"Col1":"VIN:","Col2":"4133166"}},{"WipNo":"20285","Row":{"Col1":"Make:","Col2":"Citroen"}},{"WipNo":"20285","Row":{"Col1":"Model:","Col2":"C3 Picasso"}},{"WipNo":"20285","Row":{"Col1":"Colour:"}},{"WipNo":"20285","Row":{"Col1":"Fuel Type:","Col2":"Petrol"}},{"WipNo":"20285","Row":{"Col1":"Last known odometer:","Col2":"0"}},{"WipNo":"20285","Row":{"Col1":"Next service due:","Col2":"1200 or 06/07/2018"}},{"WipNo":"20285","Row":{"Col1":"Registration date:","Col2":"06/09/2017"}},{"WipNo":"20285","Row":{"Col1":"MOT due date:","Col2":"06/07/2018"}}],"Variant":{"Class":"CAR","Desc":"Car","Variants":{"Variant":[{"Class":"BIKE","Desc":"Motorcycle"},{"Class":"CAR","Desc":"Car"},{"Class":"COMP","Desc":"Component vehicle"},{"Class":"HGV","Desc":"Heavy Goods Vehicle"},{"Class":"LCV","Desc":"Light Commercial Vehicle"}]}}},{"Type":"2","SectionDesc":"Today's Service Details","Cols":"2","DisplayRows":"6","Rows":"6","ListRow":[{"WipNo":"20285","Row":{"Col1":"Repair number:","Col2":"20285"}},{"WipNo":"20285","Row":{"Col1":"Account:","Col2":"C0002 - Service Retail Cash Sales"}},{"WipNo":"20285","Row":{"Col1":"Notes:","Col2":"Carry out repair :-"}},{"WipNo":"20285","Row":{"Col1":"Goods value:","Col2":"£52.73"}},{"WipNo":"20285","Row":{"Col1":"VAT value:","Col2":"£10.55"}},{"WipNo":"20285","Row":{"Col1":"Total value:","Col2":"£63.28"}}]},{"Type":"4","SectionDesc":"Recent Service History"}],"VHCCompleted":"0","Reminders":"0","PreviousVHC":{"Available":"0"}},"Version":"3.228","Partition":"972","Startup":"2017-09-06T15:40","RequestsServiced":"1"}}

Upvotes: 1

Views: 965

Answers (1)

dbc
dbc

Reputation: 116585

The following JSONPath query string works with Json.NET:

string key = "GetAdvisorWipDetailPageResponse.AdvisorDetailPage.ListSection[0].ListRow[?(@.Row.Col1=='VIN:')].Row.Col2";

And returns, as a result, 4133166.

Working .Net fiddle.

Why does this work? If I simplify the ListRow section of your JSON, it looks like this:

{
   "ListRow":[
      {
         "WipNo":"20285",
         "Row":{
            "Col1":"Registration:",
            "Col2":"PRA4133166"
         }
      },
      {
         "WipNo":"20285",
         "Row":{
            "Col1":"VIN:",
            "Col2":"4133166"
         }
      }
   ]
}

You are looking for an entry in the ListRow array for which Row.Col1 has a certain value, specifically "VIN:". When found, you want to select the value of Row.Col2. The JSONPath query string 

ListRow[?(@.Row.Col1=='VIN:')].Row.Col2

Does this.

(In your query, you are trying to apply a filter to objects nested directly inside objects (specifically, filtering the value of Col inside the Row object inside the ListRow array item object). This is apparently not implemented in Json.NET as of 10.0.3; see Json.NET JSONPath query not returning expected results for further discussion.)

Upvotes: 1

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