Json.NET deserializing custom object returns null

Question

I am having trouble in converting a JSON string to a C# object with Json.NET.

I used the AJAX call .ashx

$.ajax({
 url: "/Handler/Handler.ashx?WorkType=SaveData",
 type: "POST",
 data: JSON.stringify({ 'DataInfo': Info }),
 //data: "{'DataInfo':" + JSON.stringify(Info) + "}",
 dataType: "json",
 success: function (data, textStatus, jqXHR) {
 if (data.Result) {
 }
 },
 error: function (jqXHR, textStatus, errorThrown) {
 alert("Error '" + jqXhr.status + "' (textStatus: '" + textStatus + "', errorThrown: '" + errorThrown + "')");
 }
});

And my Json String is like

{
  "DataInfo": [
   {
     "EditType": "Create",
     "CustCode": "SSG",
     "KeyNoStr": "rgrg",
     "Requester": "rgrg",
     "VerificationCode": "VAVBZ",
     "Databody": "TESt123",
     "HasMap": false,
     "IsColse": false,
     "HasOrder": false,
     "IsUrgent": true
   }
  ]
}

and my .ashx Server side code is like..

public class DataInfo
{
 public string EditType { get; set; } 
 public string CustCode { get; set; }
 public string KeyNoStr { get; set; }
 public string Requester { get; set; }
 public string VerificationCode { get; set; }
 public string Databody { get; set; }
 public string HasMap { get; set; }
 public string IsColse { get; set; }
 public string HasOrder { get; set; } 
 public string IsUrgent { get; set; }
}

main function in .ashx

public void ProcessRequest(HttpContext context)
{
 Request = context.Request;
 Response = context.Response;
 string lv_strResult = string.Empty;
 DataInfo lv_oInfo = JsonConvert.DeserializeObject<DataInfo >((new StreamReader(Request.InputStream)).ReadToEnd());
}

What I am doing wrong?

• Mr. B: Try just getting the string response first and see if its empty.

Answer 1

That's because that JSON object is an Array of DataInfo, so you need to deserialize using these classes

public class DataInfo
{
 public string EditType { get; set; }
 public string CustCode { get; set; }
 public string KeyNoStr { get; set; }
 public string Requester { get; set; }
 public string VerificationCode { get; set; }
 public string Databody { get; set; }
 public bool HasMap { get; set; }
 public bool IsColse { get; set; }
 public bool HasOrder { get; set; }
 public bool IsUrgent { get; set; }
}
public class RootObject
{
 public List<DataInfo> DataInfo { get; set; }
}
//your method
public void ProcessRequest(HttpContext context)
{
 Request = context.Request;
 Response = context.Response;
 string lv_strResult = string.Empty;
 DataInfo lv_oInfo = JsonConvert.DeserializeObject<RootObject>((new StreamReader(Request.InputStream)).ReadToEnd());
 }

• JuanK: Hi @Kevin Chang Have you tested the solution?

Answer 2

Your JSON represents structure with one property named DataInfo of type List<DataInfo>

So you need to replace DataInfo lv_oInfo = JsonConvert.DeserializeObject<DataInfo >((new StreamReader(Request.InputStream)).ReadToEnd()); with

var jobject = (JObject)JsonConvert.DeserializeObject((new StreamReader(Request.InputStream)).ReadToEnd());
var di_json = jobject["DataInfo"].ToString(); // Dirty but this is the main idea
var data_infos = JsonConvert.DeserializeObject<List<DataInfo>>(di_json);

This is not the best code in the world because of double deserialization, but it shows the idea.