I have an issue with JSON serialization into a class with a dictionary property.
The whole process is a bit more complex, as an input i have a YAML file that i convert into a json using YamlDotNet and NewtonSoft like so
This is an example of the Yaml and the JSON output
some_element: '1'
should_be_dic_element:
- a: '1'
- b: '2'
{
"some_element": "1",
"should_be_dic_element": [
{
"a": "1"
},
{
"b": "2"
}
]
}
And the class
public class SomeClass
{
[JsonProperty(PropertyName = "some_element")]
public string SomeProperty { get; set; }
[JsonProperty(PropertyName = "should_be_dic_element")]
public Dictionary<string, string> Dictionary { get; set; }
}
I know the issue with Array dictionary so this are all the things I've tried.
Using Dictionary i get the following
error Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'System.Collections.Generic.Dictionary`2[System.String,System.String]' 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
Using a new class from Dictionary like so
[JsonArray]
class X : Dictionary<string, string> { }
error Value cannot be null.
Parameter name: key
Using KeyValuePair<string, string>[] / List<KeyValuePair<string, string>> the outcome is the amount of elements but with null values.
Any suggestions please ?
I think your JSON which you are attempting to de-serialize is not conforming to your class definition. Try changing the way you are generating the JSON.
For a dictionary-type structure, I would expect to see curly braces { instead of [ to begin the structure, e.g.:
{
"some_element": "1",
"should_be_dic_element": {
{
"a": "1"
},
{
"b": "2"
}
}
}
If you want to deserialize the existing JSON unchanged, try using your class definition to specify a list of dictionaries as such:
public class SomeClass
{
[JsonProperty(PropertyName = "some_element")]
public string SomeProperty { get; set; }
[JsonProperty(PropertyName = "should_be_dic_element")]
public List<Dictionary<string, string>> Dictionary { get; set; }
}
Related
I have been trying deserialiable the api and the program shows this error: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[System.Diagnostics.Activity]' 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 'activity', line 1, position 12.'
This is my code:
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thanks if someone can help me
if your json data looks like this :
jsonData = [{"id":"518523721","name":"ftyft"},
{"id":"527032438","name":"ftyftyf"},
{"id":"527572047","name":"ftgft"},
{"id":"531141884","name":"ftftft"}]
then you can try :
public class Person
{
public string Id { get; set; }
public string Name { get; set; }
}
var people = JsonConvert.DeserializeObject<List<Person>>(json);
in case of array format :
public class PersonArray
{
public Pserson[] Person{get;set;}
}
var people = JsonConvert.DeserializeObject<PersonArray>(json);
I'm trying to deserialize JSON to C# object using NewtonsoftJson.
My json looks like this:
{"something" : [ "key1" : "value1", "key2" : "value2"]}
But it's not a full json. So it should be kind of part of large object.
I can't use this solution JSON array to C# Dictionary
because I use
JsonConvert.DeserializeObject<MyObject>(json);
Does it possible to initialize object like this?
public class Something
{
[JsonProperty]
public Dictionary<string, string> MyDictionary;
}
But when I'm trying to do that I get exception:
Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the
current JSON array (e.g. [1,2,3]) into type
'System.Collections.Generic.Dictionary`2[System.String,ConsoleApp4.TxPerfMeasurements]'
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.
Input
{
"something": [
{ "key1": "value1" },
{ "key2": "value2" }
]
}
Your model should look like below
public class Something
{
public List<Dictionary<string, string>> something { get; set; }
}
Use Linq to convert to Dictionary
var result = JsonConvert.DeserializeObject<Something>(json);
var dict = result.something.SelectMany(d => d).ToDictionary(e => e.Key, e => e.Value);
Output
Problem
Heres my JSON object:
{
"1000":{
"id": "23445",
"latlon": "6780"
},
"1001":{
"id": "23454",
"latlon": "6784"
},
"1002":{
"id": "23245",
"latlon": "6180"
},
"1003":{
"id": "12345",
"latlon": "6740"
}
}
As you can see the property names are pure integers (1000, 1001, 1002, 1003)
I can't declare class variable names in integar and run System.json.Serialization.
Therefore I need to load the JSON file into:
public static Dictionary<int, NodeDetail> NodeInfo;
public class NodeDetail {
public ulong id;
public int latlon;
//Generic class serializer
//Generic class deserializer
}
Is there a library function for this? or do I have to parse the JSON string from ground up?
ps. I'm new to C#(coming from C++)
Newtonsoft.Json. You can pull it from NuGet.
Simple example:
public static T DeserializeJson<T>(string json)
{
return JsonConvert.DeserializeObject<T>(json);
}
and then
Dictionary<string, object> foo = DeserializeJson<Dictionary<string, object>>(" ... insert JSON here ... ");
EDIT: given the structure you mention in your question, you may want to deserialize into a nested dictionary:
Dictionary<int, Dictionary<long, int>> foo = DeserializeJson<Dictionary<int, Dictionary<long, int>>>(" ... insert JSON here ...");
There's also JObject (in the same Newtonsoft.Json library) which is very helpful for deserializing to something uniform that can be used.
I want to deserialize a JSON strin like this
{
"status":"1",
"since":"1245626956',
"list":{
"1":{
"item_id":"1"
},
"2":{
"item_id":"2"
}
}
}
For this I have an object that parses that
public class ListResponse
{
public String status { get; set; }
public String since { get; set; }
public IDictionary<String, Item> list { get; set; }
}
I use this sentence:
ListResponse list = JsonConvert.DeserializeObject<ListResponse>(message);
That works well but I have a problem because response can be something like this
{
"status":"1",
"since":"1245626956',
"list":[]
}
When trying to deserialize that an exception raises because needs an array to parse 'list' but my object has a IDictionary.
Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'System.Collections.Generic.IDictionary`2[System.String,Item]' 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<T> 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.
How can I handle this issue without using Linq to obtain JObject and do the mapping "by hand"?
A simple workaround would be to do this before deserializing:
yourString = yourString.Replace("\"list\":[]", "\"list\":{}");
I have the following code and json:
public class Labels
{
public Labels()
{}
public Label[] Label {get;set;}
}
public class Label
{
public Label()
{ }
public string Name { get; set; }
public int TorrentsInLabel { get; set; }
}
//...
Labels o = JsonConvert.DeserializeObject<Labels>(json);
//...
{"label":
[
["seq1",1]
,["seq2",2]
]}
I would like this array ["seq1","1"] to deserialize into Label object. What am I missing? Some attributes?
When I run I get exception: Expected a JsonArrayContract for type 'test_JSONNET.Label', got 'Newtonsoft.Json.Serialization.JsonObjectContract'.
tnx
gg
How can JsonConvert know that "seq1" corresponds to name and "1" corresponds to the TorrentsInLabel? Please have a look at JsonObjectAttribute, JsonPropertyAttribute, JsonArrayAttribute
By default a class serializes to a JSON object where the properties on the class become properties on the JSON object.
{
Name: "seq",
TorrentsInLabel: 1
}
You are trying to serialize it to an array which isn't how the Json.NET serializer works by default.
To get what you want you should create a JsonConverter and read and write the JSON for Label manually to be what you want it to be (an array).