I have a silverlight web application. From this app I am making a call to JSP pages using WebClient class. Now JSP returns a response in JSON format
{
"results":[{"Value":"1","Name":"Advertising"},
{"Value":"2","Name":"Automotive Expenses"},{"Value":"3","Name":"Business Miscellaneous"}]
}
The above response is assigned to my Stream object.
I have a c# class CategoryType
public class CategoryType
{
public string Value{get;set;}
public string Name{get;set;}
}
My aim is to convert the reponses in to Collection<CategoryType> and use it in my C# Code
As of now I am trying to use DataContractJSONSerialiser. But not sure if there is an easy and efficent way to do this. Any help would be appreciated
Its JSON and to convert it to object you need to deserialize it to object. many tools are available from Microsoft and Third party .
And you seem to be going the right way.
I have used JavascriptSerializer. See its use here http://shekhar-pro.blogspot.com/2011/01/serializing-and-deserializing-data-from.html
or use a great library JSON.Net used extensively even before Microsoft released those libraries.
Update
As you mentioned in your comments you want to convert it to Collection you could do it like this:
create array class to represent array of items.
public class CategoryTypeColl
{
public CategoryType[] results {get;set;}
}
and in your code
Collection<CategoryType> ctcoll = new Collection<CategoryType>();
JavaScriptSerializer jsr = new JavaScriptSerializer();
CategoryTpeColl ctl = jsr.Deserialize<CategoryTypeColl>(/*your JSON String*/);
List<CategoryType> collection = (from item in ctl.results
select item).ToList();
//If you have implemented Icollection then you can use yourcollection and Add items in a foreach loop.
Related
I'm trying to work with JSON files to store a Class and I'm stuck with the deserialization.
I'm using the following NameSpace:
using System.Text.Json.Serialization;
I have a very simple class, made of 2 properties:
public EnumOfType Type { get; set; }
public double Price { get; set; }
I have 4 instances of this classe that I store in a list. When quiting the application, this list is saved in a JSON file.
string jsonString;
jsonString = JsonSerializer.Serialize(myListOfInstances);
File.WriteAllText(FileName, jsonString);
When I'm opening the Application, I want the JSON file to be loaded to recreate the instances.
I'm using the following method, which apparently works well.
string jsonString = File.ReadAllText(FileName);
myListOfInstances = JsonSerializer.Deserialize<List<MyClass>>(jsonString);
So far so good. When I check the content of the list, it is correctly populated and my 4 instances are there.
But then... how to use them?
Before the JSON, I was creating each instance (for example:)
MyClass FirstInstance = New MyClass();
FirstInstance.Type = EnumOfType.Type1;
FirstInstance.Price = 100.46;
Then I could manipulate it easily, simply calling FirstInstance.
myWindow.Label1.Content = FirstInstance.Price.ToString("C");
FirstInstance.Method1...
Now that the instances are in my list, I don't know how to manipulate them individually because I don't know how to call them.
It's probably obvious to most, but I'm still in the learning process.
Thank you for your help,
Fab
Based on how you have loaded the JSON file into your program, it looks like your variable myListOfInstances already contains all four MyClass objects ready to go. At this point you can use List accessors (or Linq if you want to be fancy) and do things such as the following:
myListOfInstances[0] //Gives you the first item in the list accessed by index
myListOfInstances.First() //Gives you the first item in the list (using linq)
foreach(var item in myListOfInstances) {
// this will iterate through all four items in the list storing each instance in
//the 'item' variable
}
etc...
EDIT: From my comment below. If you need to access values in a a list directly, you can search for specific conditions in the list using linq with the 'Where' method. The syntax is something like this:
myListOfInstances.Where(x => x.Property == SomePropertyToMatch)
I mostly work on the PHP , recently have switched to ASP.NET,
When parse the JSON, I can simply use -> to get the field, e.g.
foreach(json_decode($_POST['mandrill_events']) as $event) {
$event = $event->event;
$email_type = $event->msg->metadata->email_type;
}
However, in ASP.NET , there is no action, this is my attempt code
var post_data = Request.Form["mandrill_events"];
JavaScriptSerializer ser = new JavaScriptSerializer();
var post_data_json = ser.Deserialize<Dictionary<string, string>>(post_data);
foreach (var event_obj in post_data_json) {
//how to parse the event_obj?
}
Thanks a lot for helping.
use Newtonsoft Json.NET
JsonConvert.DeserializeObject<DataModel>(json);
Unless you want to write a C# class that represents the JSON you are POSTing (the safest solution), you can use the dynamic type to create an object which will look like your JSON. You can then do something like this answer to access the properties.
This solution doesn't give you type safety and the DLR will resolve the properties of the dynamic object at runtime.
As other answers have mentioned, your life will be made much easier by using Newtonsoft JSON which will allow you to write:
dynamic events = JsonConvert.DeserializeObject<dynamic>(post_data);
foreach(dynamic evt in events)
{
string emailType = evt.msg.metadata.email_type;
}
Here is something i couldn't get around my head even after spending a few hours. Hoping someone will direct me.
I have a Dictionary object which I want to convert to JSON.
Sample code:
Dictionary<String,String> users = new Dictionary<String,String>();
Users look something like this:
{[name1, department1],[name2, department2]}
Here is the custom JSON format for each user:
public class User
{
public string name;
public string dept;
// has get and set methods for each.
}
How can I write the users Dictionary as a JSON object of type user?
Ideally if the dictionary represents a collection of user objects then it in fact should be a collection of user objects. But failing that, it can easily be transformed into one:
users.Select(u => new user { name = u.Key, dept = u.Value });
The resulting enumerable can then be serialized using pretty much any serializer.
I'm writing a Web API ApiController with several PUT methods that receive JSON data. The JSON is not deterministic and hence cannot be hard-mapped to a custom C# object, but needs to be received as Dictionaries/Sequences (Maps/Lists).
I have tried using an IDictionary for the data parm of the PUT method in the controller, and this sort of works -- the data appears to be mapped from JSON to the dictionary. However, it's necessary to declare the dictionary as <String,Object>, and there's no clear way to then retrieve the Object values as their appropriate types. (I've found a few suggested kluges in my searching, but they are just that.)
There is also a System.Json.JsonObject type which I finally managed to get loaded via NuGet, but when I use that the system does not appear to know how to map the data.
How is this typically done? How do you implement an ApiController method that receives generic JSON?
I can see three basic approaches:
Somehow make Dictionary/Sequence work with Object or some such.
Make something like System.Json.JsonObject work, perhaps by swizzling the routing info.
Receive the JSON as a byte array and then parse explicitly using one of the C# JSON toolkits available.
(As to how dynamic the data is, JSON objects may have missing entries or extraneous entries, and in some cases a particular entry may be represented as either a single JSON value or a JSON array of values. (Where "value" is JSON array, object, string, number, Boolean, or null.) In general, except for the array/not array ambiguity, the relation between keys and value types is known.)
(But I should note that this is a large project and I'll be receiving JSON strings from several other components by other authors. Being able to examine the received type and assert that it's as expected would be quite useful, and may even be necessary from a security standpoint.)
(I should add that I'm a relative novice with C# -- have only been working with it for about 6 months.)
You've got to know what kind of data you're expecting, but I have had success doing this in the past using dynamic typing.
Something like this:
[Test]
public void JsonTester()
{
string json = "{ 'fruit':'banana', 'color':'yellow' }";
dynamic data = JsonConvert.DeserializeObject(json);
string fruit = data["fruit"];
string color = data["color"];
Assert.That(fruit == "banana");
Assert.That(color == "yellow");
}
Edit:
You either need to know the type you want to deserialize to beforehand - in which case you can deserialize it to that type immediately.
Or you can deserialize it to a dynamic type, and then convert it to your static type once you know what you want to do with it.
using Newtonsoft.Json;
using NUnit.Framework;
public class DTO
{
public string Field1;
public int Field2;
}
public class JsonDeserializationTests
{
[Test]
public void JsonCanBeDeserializedToDTO()
{
string json = "{ 'Field1':'some text', 'Field2':45 }";
var data = JsonConvert.DeserializeObject<DTO>(json);
Assert.That(data.Field1 == "some text");
Assert.That(data.Field2 == 45);
}
[Test]
public void JsonCanBeDeserializedToDynamic_AndConvertedToDTO()
{
string json = "{ 'Field1':'some text', 'Field2':45 }";
var dynamicData = JsonConvert.DeserializeObject<dynamic>(json);
var data = new DTO { Field1 = dynamicData["Field1"], Field2 = dynamicData["Field2"] };
Assert.That(data.Field1 == "some text");
Assert.That(data.Field2 == 45);
}
}
I am trying to make a windows 8 Store app that gets results from a MySQL database from a PHP page as a REST service.
I'm looking for the PHP to return a JSON representation of an array of strings and have done that happily when dong the same between Javascript and PHP.
I need to take that same JSON string and use it in my C# Windows 8 store App, is there a way to take the return of that PHP page and convert it into a normal C# array, not a dictionary or more complex collection.
The database does have four fields so if i have to use a special object made for this i will, but I'd rather I didn't as this function doesn't require that amount of data.
The PHP page is like so - $search_text is passed in via a GET:
$databaseConnection = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
if ($databaseConnection->connect_error)
{
echo "Database connection failed: $databaseConnection->connect_error";
}
else
{
$search_text = $search_text."%";
$query = "SELECT DISTINCT street FROM gritroutes WHERE street LIKE ? LIMIT 5";
$statement = $databaseConnection->prepare($query);
$statement->bind_param('s', $search_text);
$statement->execute();
$statement->store_result();
$statement->bind_result($street);
$autonumber = 1;
while ($statement->fetch())
{
$resultarr[] = $street;
}
$statement->close();
echo json_encode($resultarr);
}
Just to be clear. I am writing a Windows Store App, the System.Web Namespace is unavailable so i can't use JavaScriptSerializer.
Just to add to Matthew's answer, you can deserialize using Json.NET (you can get it from NuGet), you'd do something like:
List<string> myStrings = JsonConvert.DeserializeObject<List<string>>(myJson);
This is in:
using Newtonsoft.Json;
Check out this article for practical example.
EDIT
- I'd also like to throw in this link, since it's just awesome.
I hope this helps.
Take a look at the JavaScriptSerializer class.
string myJson = "{blablabla I'm json}";
var serializer = new JavaScriptSerializer();
var myStrings = serializer.Deserialize<List<string>>(myJson);
foreach (var str in myString)
{
Console.WriteLine(str);
}
You could also use native Windows.Data.Json classes to do the parsing:
string json = #"[""item1"", ""item2"", ""item3""]";
var array = JsonArray.Parse(json).Select(i => i.GetString()).ToArray();