Question

I have a JSON string that I want to be able to amend in C#. I want to be able to update a value in the results when I meet a certain condition.

Take the following

 {
  "responseHeader":{
    "status":0,
    "QTime":0,
    "params":{
      "explainOther":"",
      "fl":"*,score",
      "indent":"on",
      "start":"0",
      "q":"*:*",
      "hl.fl":"",
      "qt":"",
      "wt":"json",
      "fq":"",
      "version":"2.2",
      "rows":"2"}
  },
  "response":{"numFound":2,"start":0,"maxScore":1.0,"docs":
  [{
        "id":"438500feb7714fbd9504a028883d2860",
        "name":"John",
        "email":"[e-mail]"
        "dateTimeCreated":"2012-02-07T15:00:42Z",
        "dateTimeUploaded":"2012-08-09T15:30:57Z",
        "score":1.0
   },
   {
        "id":"2f7661ae3c7a42dd9f2eb1946262cd24",
        "name":"David",
        "email":"[e-mail]"
        "dateTimeCreated":"2012-02-07T15:02:37Z",
        "dateTimeUploaded":"2012-08-09T15:45:06Z",
        "score":1.0
    }]
 }}

I want to be able to update the name and email element values when I find a result with a certain Id.

For example I would want to update the name and email element where that docs Id equals “438500feb7714fbd9504a028883d2860” and update the name value to Richard and the email value to [e-mail]. The result of this is shown below.

 {
  "responseHeader":{
    "status":0,
    "QTime":0,
    "params":{
      "explainOther":"",
      "fl":"*,score",
      "indent":"on",
      "start":"0",
      "q":"*:*",
      "hl.fl":"",
      "qt":"",
      "wt":"json",
      "fq":"",
      "version":"2.2",
      "rows":"2"}
  },
  "response":{"numFound":2,"start":0,"maxScore":1.0,"docs":
  [{
        "id":"438500feb7714fbd9504a028883d2860",
        "name":"Richard",
        "email":"[e-mail]"
        "dateTimeCreated":"2012-02-07T15:00:42Z",
        "dateTimeUploaded":"2012-08-09T15:30:57Z",
        "score":1.0
   },
   {
        "id":"2f7661ae3c7a42dd9f2eb1946262cd24",
        "name":"David",
        "email":"[e-mail]"
        "dateTimeCreated":"2012-02-07T15:02:37Z",
        "dateTimeUploaded":"2012-08-09T15:45:06Z",
        "score":1.0
    }]
 }}

Performance is a consideration as I will need to process many JSON strings, so please bear that in mind.

Thanks in advance
Andrew

Answer 1

You can use “Newtonsoft.Json” for this http://json.codeplex.com/

It’s very easy to use! I wrote a little example which exactly does what you wanted:

Test Method:
[C#]

    private void Test(){
        byte[] Bytes = File.ReadAllBytes("json.txt");
        string Json = Encoding.ASCII.GetString(Bytes);

        Response JsonResponse = JsonConvert.DeserializeObject<Response>(Json);

        if (JsonResponse != null){
            if (JsonResponse.response != null){
                foreach(Document Doc in JsonResponse.response.docs){
                    if (Doc.id == "2f7661ae3c7a42dd9f2eb1946262cd24"){
                        Doc.name = "David";
                        Doc.email = "[e-mail]";
                    }
                }

                string JsonMod = JsonConvert.SerializeObject(JsonResponse, Formatting.Indented);

                BinaryWriter Writer = new BinaryWriter(File.Create("JsonMod.txt"));
                Writer.Write(Encoding.ASCII.GetBytes(JsonMod));
                Writer.Close();
                Writer.Dispose();
            }
        }
    }

Json classes:
[C#]

[JsonObject(MemberSerialization.OptIn)]
public class Response{

    [JsonProperty]
    public ResponseHeader responseHeader{
        get; set;
    }

    [JsonProperty]
    public ResponseContent response{
        get; set;
    }

}

[JsonObject(MemberSerialization.OptIn)]
public class ResponseHeader{
    [JsonProperty]
    public int Status{
        get; set;
    }

    [JsonProperty]
    public int QTime{
        get; set;
    }

    [JsonProperty]
    public object Params{
        get; set;
    }
}

[JsonObject(MemberSerialization.OptIn)]
public class ResponseContent{

    [JsonProperty]
    public int numFound{
        get; set;
    }

    [JsonProperty]
    public int start{
        get; set;
    }

    [JsonProperty]
    public double maxScore{
        get; set;
    }

    [JsonProperty]
    public Document[] docs{
        get; set;
    }
}

[JsonObject(MemberSerialization.OptIn)]
public class Document{

    [JsonProperty]
    public string id{
        get; set;
    }

    [JsonProperty]
    public string name{
        get; set;
    }

    [JsonProperty]
    public string email{
        get; set;
    }

    [JsonProperty]
    public DateTime dateTimeCreated{
        get; set;
    }

    [JsonProperty]
    public DateTime dateTimeUploaded{
        get; set;
    }

    [JsonProperty]
    public double score{
        get; set;
    }
}

Oh, and please have look on the json you’ve posted – after “email”:”[e-mail]” you missed a “,” – this will lead to a parsing exception 😉

Cheers!