Develop Reference

how to get Json values which are not in a class using C#?

I have the following problem:
I am a C# beginner and I want to create a weather app using the OpenWeatherApi.
The response of the api looks like this (it´s just an example):
[
{
"name": "London",
"lat": 51.5085,
"lon": -0.1257,
"country": "GB"
},
I want to get the lat and lon values.
My C# code looks like this:
public class CoordinatesResponse
{
public double Lat { get; set; }
public double Lon { get; set; }
}
private static string _coordinatesResponse;
static void ExtractCoordinatesFromJson()
{
CoordinatesResponse coordinatesresponse = JsonConvert.DeserializeObject<CoordinatesResponse>(_coordinatesResponse);
Console.WriteLine(coordinatesresponse.Lat);
Console.WriteLine(coordinatesresponse.Lon);
}
My error is the following:
Unhandled exception. Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'WeatherApp.CoordinatesResponse' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
What do I wrong?

Your problem is in the type. Been an array, you must use List<CoordinatesResponse>:
static void ExtractCoordinatesFromJson()
{
var coordinatesresponses = JsonConvert.DeserializeObject<List<CoordinatesResponse>>(_coordinatesResponse);
foreach (var coordinatesresponse in coordinatesresponses)
{
Console.WriteLine(coordinatesresponse.Lat);
Console.WriteLine(coordinatesresponse.Lon);
}
}

To solve the issue " Cannot deserialize the current JSON array (e.g. [1,2,3])"
Follow the steps:
Go to any website that convert JSON to C# (e.g. https://json2csharp.com/).
Paste your JSON data in the JSON section and click on generate C# link button.
It will generate the object to deserialize the json array.
e.g. JsonDataService myData = JsonConvert.DeserializeObject(json);
The above object can be used to manipulate the JSON string object.

I am trying to deserialize a JSON into a list of objects using .NET 3.1

I have the following Json:
{
"Id":"2727",
"Region":"US",
"Data":[
{
"Title":"Director",
"JobDescription":"Coordinates the department activity",
"Department":"HR"
},
{
"Title":"Programmer",
"JobDescription":"Enterprise software developer",
"Department":"FR"
}
]
}
My format looks like this:
public class Data
{
public string Title { get; set; }
public string JobDescription { get; set; }
public string Department { get; set; }
}
public class Format
{
public string Id { get; set; }
public string Region { get; set; }
public List<Data> Data {get; set;}
}
I have tried to deserialize it like this:
var objects = JsonConvert.DeserializeObject<IEnumerable<Format>>(File.ReadAllText("mockJson.json")).ToList();
I am getting this exception:
An unhandled exception of type
'Newtonsoft.Json.JsonSerializationException' occurred in
Newtonsoft.Json.dll Cannot deserialize the current JSON object (e.g.
{"name":"value"}) into type
'System.Collections.Generic.IEnumerable`1[JSONParsingExample.Format]'
because the type requires a JSON array (e.g. [1,2,3]) to deserialize
correctly. To fix this error either change the JSON to a JSON array
(e.g. [1,2,3]) or change the deserialized type so that it is a normal
.NET type (e.g. not a primitive type like integer, not a collection
type like an array or List) that can be deserialized from a JSON
object. JsonObjectAttribute can also be added to the type to force it
to deserialize from a JSON object. Path 'GlobalOrgId', line 2,
position 15.

Just posting this as an answer because I think its worth making it more visible. I assumed the method call was going to have some issues with nesting lists inside a json, but I'm pleased to see it works.
Format format = JsonConvert.DeserializeObject<Format>(File.ReadAllText("mockJson.json"));
I inspected the elements and they all seem to be where they are supposed to be.
Just be careful because JsonConvert.DeserializeObject<T> returns an object of type T, not IEnumerable<T>.
When working with JSON in .NET I'd recommend moving over to the new built in stuff.
https://devblogs.microsoft.com/dotnet/net-core-image-processing/

Deserialization using newtonsoft

I'm new to C# and i want to deserialize the JSON file into the API using NewtonSoft but it lead me to this error
Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'API.JSonConfiguration.exampleLibrary' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
"To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
Path '', line 1, position 1.'"
string url = #"http://180.232.67.229/api/jfiller";
string Data = new WebClient().DownloadString(url
exampleLibrary json = JsonConvert.DeserializeObject<exampleLibrary>(Data);
MessageBox.Show(json.filler_id);
exampleLibrary Class:
public string filler_id { get; set; }
public string filler_title { get; set; }
public string filler_type { get; set; }
JSON
[
{
"filler_id":"1",
"filler_title":"Star118 E-CarDemo",
"filler_type":"1",
"filler_file":"Star118CarTeaser‌​1.mp4",
"filler_durat‌​ion":"83",
"created_a‌​t":"2017-06-10 09:08:41",
"updated":"2017-06-10 09:08:41","status":"0"
},
{
"filler_id":"2",
"filler_title":"Sta‌​r118",
"filler_type":‌​"2",
"filler_file":"S‌​tar118Solar1.PNG",
"f‌​iller_duration":"10"‌​,
"created_at":"2017-‌​06-10 09:09:26",
"updated":"2017-06-10 09:09:26","status":"0"
}
]

Try
JsonConvert.DeserializeObject<IEnumerable<exampleLibrary>>(Data);
You have an array of data but don't specify it in your JsonConvert or in your exampleLibrary Class(That I can see from your posted code).

.NET Json Serialization Exception for C#

I'm using JSON.net in C# for an Excel VSTO Add in and pulling in JSON via web service.
I have verified the JSON I pull is valid (online JSON Validator) but am unable to convert the JSON into Objects in C# to use.
When I run the code below I get the exception below.
Any ideas on who I can covert the JSON correctly?
Exception:
Newtonsoft.Json.JsonSerializationException:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'Bliss.Ribbon1+RootObject[]'
because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type
(e.g. not a primitive type like integer, not a collection type like an array or List<T>)
that can be deserialized from a JSON object.
JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Code:
public async Task<string> getline()
{
<--- Set Client, Execute Request --->
//JSON content shown below
string content = await response.Content.ReadAsStringAsync();
RootObject[] dims = JsonConvert.DeserializeObject<RootObject[]>(content);
return content;
}
public class RootObject
{
public List<string> ledger { get; set; }
public List<string> ledgerAlias { get; set; }
public List<string> entity { get; set; }
public List<string> entityAlias { get; set; }
public List<string> scenario { get; set; }
public List<string> period { get; set; }
public List<string> location { get; set; }
public List<string> measures { get; set; }
}
JSON:
{
"acc":["A","B"],
"accAlias":["ACE","BCE"],
"company":["PEP", "KO"],
"companyAlias":["Pepsi", "Coco-Cola"],
"scenario":["Sales", "Expenses"],
"year": ["2016","2017"],
"areaCode":["123","131","412"],
"clients":["32340-0120","3031-0211","3412-0142"]
}

The JSON represents a single instance of the object, not an array. So instead of this:
RootObject[] dims = JsonConvert.DeserializeObject<RootObject[]>(content)
use this:
RootObject dims = JsonConvert.DeserializeObject<RootObject>(content)
Conversely, if it should be an array, make the JSON itself an array (containing a single element) by surrounding it with brackets:
[{
"acc":["A","B"],
"accAlias":["ACE","BCE"],
"company":["PEP", "KO"],
"companyAlias":["Pepsi", "Coco-Cola"],
"scenario":["Sales", "Expenses"],
"year": ["2016","2017"],
"areaCode":["123","131","412"],
"clients":["32340-0120","3031-0211","3412-0142"]
}]
Edit: As others have also been pointing out, the properties on the JSON object don't actually match that class definition. So while it may "successfully" deserialize, in doing so it's going to ignore the JSON properties it doesn't care about and initialize to default values the class properties.
Perhaps you meant to use a different class? Or different JSON? Or rename one or more properties in one or the other?
Either way, the difference between a single instance and an array of instances is the immediate problem. But in correcting that problem you're going to move on to this next one.

The RootObject and the json are not compatible. You could deserialize using a dictionary. Try this:
var dims = JsonConvert.DeserializeObject<Dictionary<string, string[]>>(content);

JSON object deserialize to c# object - OpenTSDB

I am dealing with JSON for the first time and getting data from OpenTSDB. I've created a c# class to deserialize the JSON to but I am getting the error 'Cannot deserialize the current JSON array' as described below.
My c# code to get JSON:
var request = WebRequest.Create("http://localhost:4242/api/query?start=2013/08/21-12:00:00&end=2013/08/22-12:00:00&m=sum:tcollector.collector.lines_sent&o=&yrange=%5B0:%5D&wxh=924x773");
request.ContentType = "application/json; charset=utf-8";
string text;
try
{
var response = (HttpWebResponse) request.GetResponse();
using (var sr = new StreamReader(response.GetResponseStream()))
{
text = sr.ReadToEnd();
}
uxResponse.Text = text;
OpenTSDBResponse myObject = (OpenTSDBResponse)Newtonsoft.Json.JsonConvert.DeserializeObject(text, typeof(OpenTSDBResponse));
var variable = Newtonsoft.Json.JsonConvert.DeserializeObject(text);
//var tester = myObject;
}
catch (Exception ex)
{
uxResponse.Text = GetFullExceptionMessage(ex);
}
The JSON I am receiving from the above code (i.e. the 'text' variable):
[{
"metric":"tcollector.collector.lines_sent",
"tags":
{
"host":"ubuntu1"
},
"aggregateTags":["collector"],
"dps":
{
"1377050434":1271779.0,
"1377050494":1272073.0,
"1377050554":1272502.0,
"1377050614":1273632.0,
"1377050674":1273867.0
}
}]
My c# classes
internal class OpenTSDBResponse
{
[JsonProperty("metric")]
public string Metric { get; set; }
[JsonProperty("tags")]
public Tags Tags { get; set; }
[JsonProperty("aggregateTags")]
public string[] AggregateTags { get; set; }
[JsonProperty("dps")]
public List<TimeValue> TimeValues { get; set; }
}
internal class Tags
{
[JsonProperty("host")]
public string Host { get; set; }
}
internal class TimeValue
{
[JsonProperty("Time")]
public double Time { get; set; }
[JsonProperty("Value")]
public double Value { get; set; }
}
The error when deserializing object:
Cannot deserialize the current JSON array (e.g. [1,2,3]) into type
'MyNamespace.OpenTSDBResponse' because the type requires a JSON
object (e.g. {"name":"value"}) to deserialize correctly.To fix this
error either change the JSON to a JSON object (e.g. {"name":"value"})
or change the deserialized type to an array or a type that implements
a collection interface (e.g. ICollection, IList) like List that can
be deserialized from a JSON array. JsonArrayAttribute can also be
added to the type to force it to deserialize from a JSON array.Path
'', line 1, position 1.
Additional Information
I used the codeproject deserialize JSON project to create my basic classes, but it created a new c# property for each '"1377050434":1271779.0,' so I updated to use my TimeValue class. http://www.codeproject.com/Tips/79435/Deserialize-JSON-with-C
Question:
How do I get this into an appropriate c# class structure?
Additional Information in response to users comments below:
bjaminn's comment:
I believe the JSON you are receiving is an array. The exception is trying to say you are converting an object[] to OpenTSDBResponse when you really want OpenTSDBResponse[]. Another way to debug this would be to look at the variable variable and see what type it is in the debugger. Of course the line that throws the exception would need to be commented out.
Outcome: I modified the deserialize like this
OpenTSDBResponse[] myObject = (OpenTSDBResponse[])Newtonsoft.Json.JsonConvert.DeserializeObject(text, typeof(OpenTSDBResponse[]));
but received the following error when I ran it:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[MyNamespace.OpenTSDBResponseJsonTypes.TimeValue]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.Path '[0].dps.1377050434', line 1, position 121.
Additional Notes on working solution for other new to JSON
I have added another property to my class for the Dictionary as it's really "unix-time-stamp-data","Value". This allows me to work in c# with datetime/values. There may be a better way for casting but this works an doesn't cause any noticeable performance issues for my scenario.
[JsonProperty("dps")]
public Dictionary<string, double> TimeValues { get; set; }
public List<TimeValue> DataPoints
{
get
{
List<TimeValue> times = new List<TimeValue>();
DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);
foreach (var item in TimeValues)
{
times.Add(new TimeValue
{
Time = dtDateTime.AddSeconds(double.Parse(item.Key)).ToLocalTime(),
Value = item.Value
});
}
return times;
}
}

I believe the JSON you are receiving is an array. The exception is trying to say you are converting an object[] to OpenTSDBResponse when you really want OpenTSDBResponse[].
Another way to debug this would be to look at the variable variable and see what type it is in the debugger. Of course the line that throws the exception would need to be commented out.
Tackling new error
It looks like DPS is not a proper JSON array. You could parse it to a dictionary since it looks like the keys will be different in each JSON call.
JSON convert dictionary to a list of key value pairs
New class:
internal class OpenTSDBResponse
{
[JsonProperty("metric")]
public string Metric { get; set; }
[JsonProperty("tags")]
public Tags Tags { get; set; }
[JsonProperty("aggregateTags")]
public string[] AggregateTags { get; set; }
[JsonProperty("dps")]
public Dictionary<string,double> TimeValues { get; set; }
}

You can such so modify your Json Data and your C# Code,for example
[{
"metric":"tcollector.collector.lines_sent",
"tags":
{
"host":"ubuntu1"
},
"aggregateTags":["collector"],
"dps":
[
{"Time":"1377050434","Value":1271779.0},
{"Time":"1377050554","Value":1272502.0}
]
}]
c# Code:
You provide the data is an Array,so when you deserialize the string,you must such so use generic format of deserializeobject
object obj=Newtonsoft.Json.JsonConvert.DeserializeObject<List<OpenTSDBResponse>>(json.ToString());