We Keep Coding

NewtonSoft JsonPath with C# Syntax

I have a set of objects which I'm deserializing using NewtonSoft.Json 13.0.1. My project is using .Net 5.0 and the language is C#. I want to use JsonPath (Json Path) syntax to determine whether an object matches a given criterion, in particular, whether parent.child.property1 matches the string 'appname.' It seems that the only way I can use a filter expression is if I have an array. e.g., in the following, I have been unable to come up with a JsonPath expression which works. An example Json is as follows:
{
"parent": {
"child": {
"property1": "appname",
"property2": "57fc697c44",
"property3": "yes"
}
}}
As a workaround, what I've done is wrap the previous Json in an array, and then used a filter expression, so, with the following Json:
{
"item": [
{
"parent": {
"child": {
"property1": "appname",
"property2": "57fc697c44",
"property3": "yes"
}
}
}
]}
and this JsonPath expression:
$..[?(#.parent.child.property1=='appname')]
I get a match.
As an aside, I originally tried (notice the single dot)
$.[?(#.parent.child.property1=='appname')]
which didn't work. I don't understand why because my understanding is that '$.' refers to the root of the Json. If anyone can help me to understand this as well, I'd appreciate it.
Thank you.

How to check In C# JArray have specific key pair

I am working on JArray in .NET CORE and I am getting random structure of this one specific key, hence getting different error. I need to know if JArray has specific child Array and if Child JArray have specific key pair (NOT VALUE) i.e. value{ "Id":""} one of error is following;
Accessed JArray values with invalid key value: "id". Int32 array index expected.
at Newtonsoft.Json.Linq.JArray.get_Item(Object key) at
the standard structure I am expecting is as following;
{[value, [
{
"id": "7ef82869-e235-69a2-f81e-3a9664e89bc4",
"value": ""
}
]]}
sometime I get as, meaning throw null error where I am trying to map Id.
{[value, [
{
"value": ""
}
]]}
and some Time I don't get this property at all
I am trying following check to cover all scenario but Its not really working.
code
if (answerItems.value != null && answerItems.value.HasValues && answerItems.value["id"]!=null)
{

I received some constructive criticism on the brevity of my answer so I figured I would elaborate to help you through your issue.
First, let's take a look at your JSON. In short, it isn't valid. In fact, it isn't even close to valid JSON. I can only assume you meant something like this:
{
"values" : [{ "id" : "7ef82869-e235-69a2-f81e-3a9664e89bc4", "value": "" }]
}
I would suggest that anytime you are trying to parse data like this and you run into issues you start trouble shooting by validating the data itself. I like to use JSONLint for this.
Next, it is difficult from your example code to tell exactly what you are trying to do. I can only guess that you are attempting to use the dynamic object method of parsing and working with the data. A downside to this method is it is difficult to validate your data before you work with it.
Instead, I would use the Newtonsoft.Json.Linq.JObject.Parse method. This gives you some tools for working with and validating the information. Below I have included a very simple example of how this would be done.
using System;
using Newtonsoft.Json.Linq;
public class Program
{
public static void Main()
{
string json = "{ \"values\": [{ \"id\": \"7ef82869-e235-69a2-f81e-3a9664e89bc4\", \"value\": \"\" }] }";
JObject obj = JObject.Parse(json);
// Check to see if we got our value array
if (obj.ContainsKey("values")) {
JArray values = (JArray)obj["values"];
// Do we have any values in our array?
if (values.Count > 0) {
JObject firstItem = (JObject)values[0];
// We check to see if we have an ID parameter
if (firstItem.ContainsKey("id")) {
Console.WriteLine(firstItem["id"]);
}
}
}
}
}
As I mentioned in my original post, I would strongly recommend reviewing the Newtonsoft.Json documentation.

Deserialize complex JSON data in C#

I'm just an amateur in C# programming. Now i have a JSON data that looks like following
{
type: "xxx",
width: "xxx",
dataSource: {
"chart": {
"caption": "xxx"
},
"data": [
{},
{}
]
}
}
I'm having the whole data as escaped string. now after Unescape when I'm using JavaScriptSerializer as follows
var data = ser.Deserialize<Dictionary<String, Object>>(chartData);
I'm able to get the "type", "width" as
data["width"]
data["type"]
Now I have to get the value of "caption". Any suggestion how to get that, I believe the dictionary structure need to be changed but I'm stacked for my lack of knowledge in C#

If you know the object's scheme you man want to create a class that represents in and then deserialize the json into it:
YourKnownClass obj = JsonConvert.DeserializeObject<YourKnownClass>(json);
Console.WriteLine(obj.dataSource.chart.caption.Value);
Another option is by using a dynamic type (There is no good reason using a dynamic object if you know the schema and can create a matching C# class. This has a performance impact as well):
dynamic obj = JsonConvert.DeserializeObject<dynamic>(json);
Console.WriteLine(obj.dataSource.chart.caption.Value);
BTW, In this example i'm using json.net which is a popular library.

JSON.Net, customizing serialization of List<T>

I'm serializing a List<T>, which I suppose is an array of objects when you think about it. When serializing the populated List<T>, I get a result similar to the following:
[
{
"foo": "a1",
"bar": "b1"
},
{
"foo": "a2",
"bar": "b2"
},
{
"foo": "a3",
"bar": "b3"
}
]
This is of course a json array of objects as you'd expect. However, I have a different need. I require the serialization of the List<T> to be separate objects as shown.
{
"foo": "a1",
"bar": "b1"
}
{
"foo": "a2",
"bar": "b2"
}
{
"foo": "a3",
"bar": "b3"
}
I'm planning to use RegEx to update the json string, but before I went through that step, I wanted to find out if there is an in-the-box solution in json.net to deal with specific formatting needs. Granted, I have not read every line of documentation but, I've read a good bit of it and nothing stood out.
Thanks.

My approach was wrong here. The real issue is at the target for where the json will be ingested. Rather than trick json.net into serializing invalid json, I am going to refocus my energy on why the target system is interpreting my json file incorrectly.

Why dont try to use NEWTONSOFT it will make all the work for you just have to implement the library and return the Json ready to use
public static string ToJson(object obj)
{
//Remember to JSON.parse() in aspx so you can work with data returned
return Newtonsoft.Json.JsonConvert.SerializeObject(obj);
}
Hope this help you

Dealing with a JSON object's property called "private" in C# with Newtonsoft's JSON.NET

I am trying to parse a json string returned from the xively feed from an Air Quality Egg. One of the properties says whether the xively feed is public or private. The property is called private and takes the string value "true" or "false". To get data from the feed I am calling xively's Historical Data REST API which successfully returns me valid JSON. I am then using JSON.NET to parse the JSON in C#. My parsing starts thus:
dynamic historicalDatapoints = JValue.Parse(jsonString) as JObject;
if (historicalDatapoints != null)
{
var id = historicalDatapoints.id;
var title = historicalDatapoints.title.ToString();
var privacy = bool.Parse(historicalDatapoints.private.ToString())
// More parsing
}
I have a problem with that last line of code. C# will not let me refer to the property called "private". Here's the corresponding (redacted) JSON:
{
"id": 000000843,
"title": "Blah Road Egg 02",
"private": "false",
//...
}
Using JSON.NET how should I parse out the property private?

Try historicalDatapoints.#private to access that value. If that doesn't work then you could also try historicalDatapoints["private"]