I have a json string like this:
{
"ipaddress": "xxx",
"hostname": "comcast.xxx",
"popup": {
"position": "1256",
"pagename": "home"
}
}
In my Windows Form code I've been using JavaScriptSerializer for phare those line to dictionary.
var obj = new JavaScriptSerializer().Deserialize<Dictionary<string, object>>(json);
It is working fine at the moment, but I don't know how to get value inside popup? Because it's another dictionary.
[7] = {[popup, System.Collections.Generic.Dictionary`2[System.String,System.Object]]}
The fastest (yet unsafe) way of doing it is like this is via the indexer:
First extract the first dictionary and cast, since the first dictionary will yield an object of type object:
var popup = (Dictionary<string, object>)obj["popup"];
Then, you extract the values based on keys:
var position = popup["position"];
var pagename = popup["pagename"];
If you're not sure both keys will exist in the result, you can use Dictionary.TryGetValue if they exist:
obj position;
if (!popup.TryGetValue("position", out position))
{
// Key isn't in the dictionary.
}
Use JSON .Net, then simply:
JObject dynJson = JObject.Parse(jsonString);
followed by:
string data = dynJson["popup"]["position"];
JObject.Parse
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 am trying to convert a JSON array to a C# dictionary.
My Box class has "id" and "color" properties.
{
"boxes" [
{"id":0, "color":"red"},
{"id":1, "color":"green"},
{"id":2, "color":"blue"}
]
}
I've tried a few things, but haven't had any luck getting this to work yet.
List<Box> jsonResponse = JsonConvert.DeserializeObject<List<Box>>(File.ReadAllText(filePath));
Well the thing is that your Dictionary is in nested property.
And even more - it's not really a dictionary. It is an array of objects where each object consists of two fields - id and color (whereas in dictionary we have key-value pairs).
You could deserialize your json into anonymous object with correct structure and then get the array of boxes out of it and convert it to dictionary:
var box = new { id = 0, name = "" };
var jsonObj = new { boxes = new[] { box } };
var dict = JsonConvert.DeserializeAnonymousType(myJson, jsonObj).boxes
.ToDictionary(b => b.id, b => b.name);
JSON doesn't need {} at the top level - so you can just have your list of items in {}'s surrounded by [].
[
{"id":0, "color":"red"},
{"id":1, "color":"green"},
{"id":2, "color":"blue"}
]
I have a Json string like below and this is only a small snippet. The number in quotation marks is a Unix Time which i will need to use to iterate over each object.
{
"result": {
"1534860000": [
"1534860000",
19,
41
],
"1534863600": [
"1534863600",
11,
16
],
"1534867200": [
"1534867200",
2,
5
]
}
}
But when I attempt to extract the data in the arrays I get an error:
System.InvalidOperationException: 'Cannot access child value on Newtonsoft.Json.Linq.JProperty.'
Code:
JObject jsonObj = JObject.Parse(response);
string unixTime = Helpers.ConvertToUnix(yesterday.AddHours(hour)).ToString();
foreach (var obj in jsonObj["result"])
{
var array = obj[unixTime]; //here is where the error occurs
}
Anyone able to shed some light on what I am missing?
If we simplify your example code a little to remove the unixTime element (let's just hardcode it for now), we end up with this:
JObject jsonObj = JObject.Parse(response);
string unixTime = "1534860000";
At this stage, we have jsonObj which refers to the root of the JSON object and has a single property of result. Repeating your foreach here for context:
foreach (var obj in jsonObj["result"])
{
var array = obj[unixTime]; //here is where the error occurs
}
You end up with obj referring to the JSON path of result.1534860000. The problem is you're then looking for a property 1534860000 at this JSON path (result.1534860000.1534860000), which does not exist.
You can just get the value directly, like so:
var array = obj["result"][unixTime]
Of course, this requires some error-checking for ensuring the path exists, etc, but it demonstrates the point.
After some help from Kirk Larkin I thought I would post a code snippet up.
JObject jsonObj = JObject.Parse(response);
int hour = 0;
string unixTime = Helpers.ConvertToUnix(yesterday.AddHours(hour)).ToString();
var array = jsonObj["result"][unixTime];
It now returns the contents of the array.
I'm trying to get all of the "last" values from this JSON here:
{"btc":{
"usd": {
"bitfinex": {
"last": "1191.60",
"volume": "1.99324e+7"
},
"bitstamp": {
"last": "1193.06",
"volume": "8.73693e+6"
},
"btce": {
"last": "1174.27",
"volume": "6.03521e+6"
}
}
}
But for some reason I can only access "btc" and "usd". I can't get anything out of it including the "last" values. Here is the code i'm using:
private string GetPrice()
{
WebClient wc = new WebClient();
var data = wc.DownloadString("http://preev.com/pulse/units:btc+usd/sources:bitfinex+bitstamp+btce");
JObject o = JObject.Parse(data);
string response = o["btc"].ToString();
return response;
}
If I change it to:
o["last"].ToString();
It just doesn't return anything. Can someone please provide me with a solution? I also tried making a key/value dict out of it and looping over each pair. Did not work.
The JObject structure is similar to a class with properties, so the first-level indexer ["btc"] returns another object that you have to query for its own properties ["usd"]
You can also opt for using JObject.SelectToken, generally not a bad idea. Other answers have shown how to chain the indexers but that's hard to read and maintain. Instead you can do:
jObj.SelectToken("btc[0].usd[0].bitstamp[0].last").ToString();
Further you can use the power of this syntax for other queries:
// a list o all the 'last' values
jObj.SelectTokens("btc.usd.*.last").Select(t=>t.ToString()).ToList();
Another advantage, if you're building a more complex system, is that you could put the queries in a config file or attributes etc to make them more manageable or deploy logic changes without rebuilding.
Yet another approach would be to build your own class structure and deserialize your json into it, so you have strongly typed values (double instead of string for the values for example)
public class btc {
public usd usd {get;set;}
}
public class usd....
var btcLoaded = JsonConvert.DeserializeObject<btc>(jsonString);
var lastBitstamp = btc.usd.bitstamp.last;
Use: o["btc"]["usd"]["bitfinex"]["last"].ToString() to get the 'last' value of 'bitfinex'.
After parsing the JSON whenever you index the o variable you are indexing from the root of the JSON. In order to access nested properties like 'last' you will need to index into the next level of the JSON as such:
var bitfinex = o["btc"]["usd"]["bitfinex"]["last"].ToString();
var bitstamp = o["btc"]["usd"]["bitstamp"]["last"].ToString();
var btce = o["btc"]["usd"]["btce"]["last"].ToString();
To reduce the repetition you could iterate over the properties under the btc.usd field.
if u want to all last values use this..
decimal[] lastValues = obj.SelectTokens("$..last").ToArray()
.Select(a => a.Parent.ToObject<decimal>()).ToArray();
if u want to dictionary, use this..
var dictionary = obj["btc"]["usd"].Select(a =>
new
{
Key = ((JProperty)a).Name,
Value = a.First["last"].ToObject<decimal>()
})
.ToDictionary(a => a.Key, a => a.Value);
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();