I have an application that is written on top of ASP.NET MVC. In one of my controllers, I need to create an object in C# so when it is converted to JSON using JsonConvert.SerializeObject() the results looks like this
[
{'one': 'Un'},
{'two': 'Deux'},
{'three': 'Trois'}
]
I tried to use Dictionary<string, string> like this
var opts = new Dictionary<string, string>();
opts.Add("one", "Un");
opts.Add("two", "Deux");
opts.Add("three", "Trois");
var json = JsonConvert.SerializeObject(opts);
However, the above creates the following json
{
'one': 'Un',
'two': 'Deux',
'three': 'Trois'
}
How can I create the object in a way so that JsonConvert.SerializeObject() generate the desired output?
Your outer JSON container is an array, so you need to return some sort of non-dictionary collection such as a List<Dictionary<string, string>> for your root object, like so:
var opts = new Dictionary<string, string>();
opts.Add("one", "Un");
opts.Add("two", "Deux");
opts.Add("three", "Trois");
var list = opts.Select(p => new Dictionary<string, string>() { {p.Key, p.Value }});
Sample fiddle.
Related
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();
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();
I need to get currency values list in C# from here:
http://openexchangerates.org/currencies.json
which produces this kind of output:
{
"AED": "United Arab Emirates Dirham",
"AFN": "Afghan Afghani",
"ALL": "Albanian Lek",
"AMD": "Armenian Dram",
"ANG": "Netherlands Antillean Guilder",
"AOA": "Angolan Kwanza"
// and so on
}
I managed to get a string containing values above using C#, but I cannot find a way to deserialize that string into any custom class or anonymous object, so I am wondering how to do that?
Also, I am trying to use Json.NET to do that, but so far couldn't find a solution...
using Json.Net
var dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(jsonString);
--EDIT--
You can make it shorter
WebClient w = new WebClient();
string url = "http://openexchangerates.org/currencies.json";
var dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(w.DownloadString(url));
A solution using only .Net 4.0 and no third party libraries:
string url = "http://openexchangerates.org/currencies.json";
var client = new System.Net.WebClient();
string curStr = client.DownloadString(url);
var js = new System.Web.Script.Serialization.JavaScriptSerializer();
var res = (js.DeserializeObject(curStr) as Dictionary<string, object>)
.Select(x => new { CurKey = x.Key, Currency = x.Value.ToString() });
Outputs a list of anonymous objects with the keys and values from the list as properties.
Enjoy :)
How to use fastJSON (or some other JSON lib, possibly) to dump some data into a dictionary format, e.g. {"key1": "valstring", "key2": 1234}?
If I try to dump Dictionary<string, Object> I get something like [{"k":"key1","v":"valstring"},{"k":"key2","v":1234}] instead.
We use Json.NET at our office. We send json objects between python and C#. We ran into the same problem, though ours was just the differences in how the languages naturally serialized it.
The best part about it, if I'm remember correctly, is that it had this behavior right out of the box.
var dict = new Dictionary<string, string>();
dict.Add("key", "val");
dict.Add("key2", "val2");
string json = JsonConvert.SerializeObject(dict);
Json should equal { "key": "val", "key2": "val2" }
You just can use JavaScriptSerializer to create your solution, it's native for .Net.
var dict = new Dictionary<string, string>();
dict.Add("key", "val");
dict.Add("key2", "val2");
var serializer = new JavaScriptSerializer();
string json = serializer.Serialize(dict);
And you'l get result you are expected: {"key1": "valstring", "key2": 1234}
(fastJSON) You need use some parameters parameters:
_jsonParameters = new JSONParameters
{
EnableAnonymousTypes = true,
SerializeToLowerCaseNames = true,
UseFastGuid = false,
KVStyleStringDictionary = false <---- THIS
};
}
JSON.ToJSON(obj, _jsonParameters)
PHP code to make an array
$tag = array(
'tag_uid' => 1234,
'x' => 0,
'y' => 0
);
$tags[] = $tag;
OUTPUT: {"x":"0","y":"0","tag_uid":"1234"}
I want to make this as JSON array in C# with the same OUTPUT for that I need help, I can't figure out which array it will be? a simple array or what.
I have tag_uid which i can pass to function and i am using JSON.NET I don't know what should i need to write in the JsonArry function but I have tried to following
public JsonArray CreatePhotoTag(string userId)
{
Dictionary<string, object> tagParameters = new Dictionary<string, object>();
tagParameters.Add("x", "0");
tagParameters.Add("y", "0");
tagParameters.Add("tag_uid", userId);
JsonArray tagsarray = ???
return tagsarray ;
}
Please help me
I recommend switching to ServiceStack.NET Text. It is incredibly fast compared to JSON.NET.
You can serialize it like this:
ServiceStack.NET
var jsonSerializer = new JsonSerializer<Dictionary<String, Object>>();
var tagsArray = jsonSerializer.SerializeToString(tagParameters);
If you really want to use JSON.NET
JSON.NET
var tagsArray = JsonConvert.SerializeObject(tagParameters, Formatting.Indented);