Develop Reference

Use C# anonymous object to generate a json string where the property name is not a legal C# variable name

To succinctly generate the json string {"limit": 1} in C#, I can serialize an equivalent anonymous object like so:
var s = JsonSerializer.Serialize(new { limit = 1 });
What if I want to to generate {"$limit": 1} instead? Is there any way of doing that with an anonymous object, or do I have to bring out the big guns?

I doubt that there is a way to achieve this with anonymous objects.
You can use JsonNode API introduced in .NET 6 for System.Text.Json (the succinct syntax uses indexer and implicit conversion from int to JsonNode):
var serialize = JsonSerializer.Serialize(new JsonObject{["$limit"] = 1});
Other options: use dictionaries or create a type and use JsonPropertyNameAttribute (I assume this one is mentioned as "big guns") .

you can try this
var json = System.Text.Json.JsonSerializer.Serialize(new Dictionary<string, int> { { "$limit", 1 } });
result
{"$limit":1}
or even more complicated
var json = System.Text.Json.JsonSerializer.Serialize(new Dictionary<string, Dictionary<string, object>> { { "$limit0", new Dictionary<string, object> { { "$limit", 1 } } }});
//or
var s = System.Text.Json.JsonSerializer.Serialize(new Dictionary<string, object> { { "$limit0", new { limit = 1 } } });
results
{"$limit0":{"$limit":1}}
//or
{"$limit0":{"limit":1}}

Json newtonsoft : Deserialize string array from an Object

My JSON is a very long one and i am fetching only one section "parent_crumbs" from the long JSON
...................,
"parent_crumbs":["Platforms","New platform"],
"promise_by":"2016-08-01",
....
The code I used to fetch value of "parent_crumbs" is
JObject lp_p = JObject.Parse(response_json);
string val= lp_p["parent_crumbs"].ToString();
This returns the following value
"[\r\n \"Platforms\",\"New platform\"\r\n]"
Now I have to do a comparison with the first value from the array as the string is available in a Dictionary as key value and if available return ID
Packages = new Dictionary<string, int>();
Packages.Add("Platforms", 10212);
Packages.Add("New platform", 10202);
Packages.Add("Unknown platform", 10203);
int category=
if(Packages.ContainsKey(val))
{
Packages.TryGetValue(val, out category);
}
So with current code I can't do the comparison straight away due to presence of [\r\n etc.
How to get the value as a string Array without special chars like [\r\n .
Making Model Classes for the JSON for deserialization is not preferred way for me. Since creating class is a big job for me as lot of properties are there in JSON and is dynamic of nature

We can use the below code
var input = "[\r\n \"Platforms\",\"New platform\"\r\n]";
var array =(JArray) JsonConvert.DeserializeObject(input);
bool isEqual = array[0].Value<string>() == "Platforms";

you could also convert it to array with Linq
using System.Linq;
var tmp = lp_p["parent_crumbs"].Select(x => x.ToString());
foreach (var x in tmp)
{
Console.WriteLine(x.ToString());
}
By using Select, it will help you convert it to array rather than to string

You can use DeserializeAnonymousType method for that:
var myType = new
{
parent_crumbs = new []{ "" },
promise_by = default(DateTime)
};
var result = JsonConvert.DeserializeAnonymousType(json, myType);
int category = 0;
string key = result.parent_crumbs[0];
if(Packages.ContainsKey(key))
{
Packages.TryGetValue(key, out category);
}
References: DotNetFiddle Example, DeserializeAnonymousType

How to handle value has properties in json? [duplicate]

I'm quite new to JSON, and am currently learning about (de)serialization.
I'm retrieving a JSON string from a webpage and trying to deserialize it into an object. Problem is, the root json key is static, but the underlying keys are dynamic and I cannot anticipate them to deserialize. Here is a mini example of the string :
{
"daily": {
"1337990400000": 443447,
"1338076800000": 444693,
"1338163200000": 452282,
"1338249600000": 462189,
"1338336000000": 466626
}
}
For another JSON string in my application, I was using a JavascriptSerializer and anticipating the keys using class structure. What's the best way to go about deserializing this string into an object?

Seriously, no need to go down the dynamic route; use
var deser = new JavaScriptSerializer()
.Deserialize<Dictionary<string, Dictionary<string, int>>>(val);
var justDaily = deser["daily"];
to get a dictionary, and then you can e.g.
foreach (string key in justDaily.Keys)
Console.WriteLine(key + ": " + justDaily[key]);
to get the keys present and the corresponding values.

You can use dynamic in .NET 4 or later. For example with JSON.NET I can do:
dynamic obj = JsonConvert.Deserialize<dynamic>("{x: 'hello'}");
You can then do:
var str = obj.x;
However, unsure how it will handle numeric keys. You can of course just use JObject directly itself, for example:
var obj = JObject.Parse("{'123456': 'help'}");
var str = obj["123456"];

Whenever you have JSON with dynamic keys it can usually be deserialized into a Dictionary<string, SomeObject>. Since the inner JSON keys are dynamic (in this question) the JSON can be modelled as:
Dictionary<string, Dictionary<string, int>>
I would recommend using NewtonSoft.Json (JSON.Net) or System.Text.Json (if you're working in .NET-Core 3.0 and up).
Newtonsoft.Json
Use DeserializeObject<T> from JsonConvert:
var response = JsonConvert.DeserializeObject<Dictionary<string, Dictionary<string, int>>>(json);
System.Text.Json
Use Deserialize<T> from JsonSerializer:
var response = JsonSerializer.Deserialize<Dictionary<string, Dictionary<string, int>>>(json);

This is not convenient to use, because in с# can not be defined a variable starts with a number. Add prefix to keys.
Or try this:
string json = "
{ daily:[
{ key: '1337990400000', val:443447 },
{ key: '1338076800000', val:444693 },
{ key: '1338163200000', val:452282 },
{ key: '1338249600000', val:462189 },
{ key: '1338336000000', val:466626 }]
}";
public class itemClass
{
public string key; // or int
public int val;
}
public class items
{
public itemClass[] daily;
}
items daily = (new JavascriptSerializer()).Deserialize<items>(json);
Then you can:
var itemValue = items.Where(x=>x.key=='1338163200000').Select(x=>x.val).FirstOrDefault();

Deserialising a list of lists where outer list has no identifier without hard coding [duplicate]

I'm quite new to JSON, and am currently learning about (de)serialization.
I'm retrieving a JSON string from a webpage and trying to deserialize it into an object. Problem is, the root json key is static, but the underlying keys are dynamic and I cannot anticipate them to deserialize. Here is a mini example of the string :
{
"daily": {
"1337990400000": 443447,
"1338076800000": 444693,
"1338163200000": 452282,
"1338249600000": 462189,
"1338336000000": 466626
}
}
For another JSON string in my application, I was using a JavascriptSerializer and anticipating the keys using class structure. What's the best way to go about deserializing this string into an object?

Seriously, no need to go down the dynamic route; use
var deser = new JavaScriptSerializer()
.Deserialize<Dictionary<string, Dictionary<string, int>>>(val);
var justDaily = deser["daily"];
to get a dictionary, and then you can e.g.
foreach (string key in justDaily.Keys)
Console.WriteLine(key + ": " + justDaily[key]);
to get the keys present and the corresponding values.

You can use dynamic in .NET 4 or later. For example with JSON.NET I can do:
dynamic obj = JsonConvert.Deserialize<dynamic>("{x: 'hello'}");
You can then do:
var str = obj.x;
However, unsure how it will handle numeric keys. You can of course just use JObject directly itself, for example:
var obj = JObject.Parse("{'123456': 'help'}");
var str = obj["123456"];

Whenever you have JSON with dynamic keys it can usually be deserialized into a Dictionary<string, SomeObject>. Since the inner JSON keys are dynamic (in this question) the JSON can be modelled as:
Dictionary<string, Dictionary<string, int>>
I would recommend using NewtonSoft.Json (JSON.Net) or System.Text.Json (if you're working in .NET-Core 3.0 and up).
Newtonsoft.Json
Use DeserializeObject<T> from JsonConvert:
var response = JsonConvert.DeserializeObject<Dictionary<string, Dictionary<string, int>>>(json);
System.Text.Json
Use Deserialize<T> from JsonSerializer:
var response = JsonSerializer.Deserialize<Dictionary<string, Dictionary<string, int>>>(json);

This is not convenient to use, because in с# can not be defined a variable starts with a number. Add prefix to keys.
Or try this:
string json = "
{ daily:[
{ key: '1337990400000', val:443447 },
{ key: '1338076800000', val:444693 },
{ key: '1338163200000', val:452282 },
{ key: '1338249600000', val:462189 },
{ key: '1338336000000', val:466626 }]
}";
public class itemClass
{
public string key; // or int
public int val;
}
public class items
{
public itemClass[] daily;
}
items daily = (new JavascriptSerializer()).Deserialize<items>(json);
Then you can:
var itemValue = items.Where(x=>x.key=='1338163200000').Select(x=>x.val).FirstOrDefault();

How to parse JSON array (as a string) to Dictionary<string,string> in C#?

I have a string in the following format:
{ "Updated" : [ { "FIRST_NAME" : "Aaa", "LAST_NAME" : "Bbb" } ] }
How can I get a dictionary out of this so I can call dict["FIRST_NAME"]?
I've tried the following, but I think they don't work because my string is a JSON array? If that's the case, how do I change it to a regular JSON string? I don't think it needs to be an array with the simple type of data that is in it... The size of the array will never be more than 1 - i.e., there will be no repeating fields.
Dictionary<string, string> dict = serializer.Deserialize<Dictionary<string, string>>(jsonString); //didn't work
JArray jArray = JArray.Parse(jsonString); //didn't work

What you are having is a complex object, which can be parsed as a Dictionary of an Array of a Dictionary!
So you can parse it like:
var dic = serializer.Deserialize<Dictionary<string, Dictionary<string, string>[]>>(jsonString)["Updated"][0];
var firstName = dic["FIRST_NAME"];
var lastName = dic["LAST_NAME"];

It might be easier to just work with a dynamic variable. See Deserialize JSON into C# dynamic object? for more details.