I got a Windows Phone 8.1 app.
I am trying to parse a list of objects returned by my Web API call.
On my server I have this code:
Default.aspx:
[WebMethod]
public static List<Shared.PremisesResponse> GetPremises(string emailaddress)
{
Premises premises = new Premises();
return premises.GetPremises(emailaddress);
}
In that premise object class
public List<Shared.PremisesResponse> GetPremises(string emailAlias)
{
DAL dal = new DAL();
List<Shared.PremisesResponse> premises = new List<Shared.PremisesResponse>();
try
{
DataSet dtMacs = dal.GetMacs(emailAlias);
for (int index = 0; index < dtMacs.Tables[0].Rows.Count; index++)
{
Shared.PremisesResponse itemMAC1 = new Shared.PremisesResponse();
itemMAC1.PremiseName = dtMacs.Tables[0].Rows[index]["PremiseName"].ToString().Trim();
itemMAC1.Alias = dtMacs.Tables[0].Rows[index]["Alias"].ToString().Trim();
premises.Add(itemMAC1);
}
}
catch (Exception ex)
{
Email2.SendError("Premises.GetPremises:" + ex.ToString(), emailAlias);
Shared.PremisesResponse itemMAC1 = new Shared.PremisesResponse();
itemMAC1.PremiseName = "ERROR";
itemMAC1.Alias = ex.ToString();
premises.Add(itemMAC1);
}
return premises;
}
The class Shared.Premise:
public class PremisesResponse
{
public string PremiseName;
public string Alias;
}
In my WP8.1 client app:
public async static Task<List<D2>> GetPremises( string emailaddress)
{
List<D2> premises = new List<D2>();
try
{
using (var client = new HttpClient())
{
var resp = await client.PostAsJsonAsync("http://my url/NativeApp/Default.aspx/GetPremises",
new { emailaddress = emailaddress });
var str = await resp.Content.ReadAsStringAsync();
var premisesResponse = JsonConvert.DeserializeObject<List<D2>>(str);
foreach (var pr in premisesResponse)
{
D2 d2 = new D2();
d2.Alias = pr.Alias;
d2.PremiseName = pr.PremiseName;
premises.Add(d2);
}
}
}
catch (Exception ex)
{
//evMessage(Enums.MessageType.Error, serverRegister);
}
return premises;
}
And the objects I am using in my client:
public class D2
{
public string __type { get; set; }
public string PremiseName;
public string Alias;
}
public class PremisesResponse
{
public D2 d { get; set; }
}
'var str' returns this value:
{"d":[{"__type":"InformedMotionBiz.Shared+PremisesResponse","PremiseName":"Informatica 2000","Alias":"9A5C3-E1945-3D315-BB43C"},{"__type":"InformedMotionBiz.Shared+PremisesResponse","PremiseName":"My Office","Alias":"40387-69918-FC22F-C444B"}]}
The error occurs on this line:
var premisesResponse = JsonConvert.DeserializeObject<List<PremisesResponse>>(str);
The error message is:
[Informed.D2]' 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 'd', line 1, position 5.
I have no problems returning a single value, just with returning a list of this object.
Any pointers would be helpful.
Thanks
You're trying to deserialize a List<D2> rather than a single D2 object:
public class PremisesResponse
{
public D2[] d { get; set; }
}
And then simply:
PremisesResponse response = JsonConvert.DeserializeObject<PremisesResponse>(str);
Related
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Facebook;
using Newtonsoft.Json;
namespace facebook
{
class Program
{
static void Main(string[] args)
{
var client = new FacebookClient(acc_ess);
dynamic result = client.Get("fql", new { q = "select target_id,target_type from connection where source_id = me()"});
string jsonstring = JsonConvert.SerializeObject(result);
//jsonstring {"data":[{"target_id":9503123,"target_type":"user"}]}
List<RootObject> datalist = JsonConvert.DeserializeObject<List<RootObject>>(jsonstring);
}
public class Datum
{
public Int64 target_id { get; set; }
public string target_type { get; set; }
}
public class RootObject
{
public List<Datum> data { get; set; }
}
}
}
Cannot deserialize the current JSON object (e.g. {"name":"value"})
into type
'System.Collections.Generic.List`1[facebook.Program+RootObject]'
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
I looked at other posts.
My json looks like this:
{"data":[{"target_id":9503123,"target_type":"user"}]}
To make it clear, in addition to #SLaks' answer, that meant you need to change this line :
List<RootObject> datalist = JsonConvert.DeserializeObject<List<RootObject>>(jsonstring);
to something like this :
RootObject datalist = JsonConvert.DeserializeObject<RootObject>(jsonstring);
As the error message is trying very hard to tell you, you can't deserialize a single object into a collection (List<>).
You want to deserialize into a single RootObject.
Can you try to change your json without data key like below?
[{"target_id":9503123,"target_type":"user"}]
That happened to me too, because I was trying to get an IEnumerable but the response had a single value. Please try to make sure it's a list of data in your response. The lines I used (for api url get) to solve the problem are like these:
HttpResponseMessage response = await client.GetAsync("api/yourUrl");
if (response.IsSuccessStatusCode)
{
IEnumerable<RootObject> rootObjects =
awaitresponse.Content.ReadAsAsync<IEnumerable<RootObject>>();
foreach (var rootObject in rootObjects)
{
Console.WriteLine(
"{0}\t${1}\t{2}",
rootObject.Data1, rootObject.Data2, rootObject.Data3);
}
Console.ReadLine();
}
Hope It helps.
The real problem is that you are using dynamic return type in the FacebookClient Get method. And although you use a method for serializing, the JSON converter cannot deserialize this Object after that.
Use insted of:
dynamic result = client.Get("fql", new { q = "select target_id,target_type from connection where source_id = me()"});
string jsonstring = JsonConvert.SerializeObject(result);
something like that:
string result = client.Get("fql", new { q = "select target_id,target_type from connection where source_id = me()"}).ToString();
Then you can use DeserializeObject method:
var datalist = JsonConvert.DeserializeObject<List<RootObject>>(result);
Hope this helps.
public partial class tree
{
public int id { get; set; }
public string name { get; set; }
public string sciencename { get; set; }
public int familyid { get; set; }
}
private async void PopulateDataGridView()
{
//For Single object response
tree treeobj = new tree();
treeobj = JsonConvert.DeserializeObject<tree>(Response);
//For list of object response
List<tree> treelistobj = new List<tree>();
treelistobj = JsonConvert.DeserializeObject<List<tree>>(Response);
//done
}
I am working on 2 web applications; A & B. now i have a shared class named CRUDOutput as follow on both web applications:-
public class CRUDOutput
{
public Operation4 operation { get; set; }
}
public class Operation4
{
public Result result { get; set; }
public string name { get; set; }
}
public class Result
{
public string status { get; set; }
public string message { get; set; }
}
now inside web application A i am returning the following:-
[HttpPost]
public ActionResult CreateResource(CreateResource cr)
{
List<CRUDOutput> co = new List<CRUDOutput>();
co.Add(JsonConvert.DeserializeObject<CRUDOutput>(crudoutput));
co.Add(JsonConvert.DeserializeObject<CRUDOutput>(crudoutput2));
return Json(JsonConvert.SerializeObject(co));
}
now from web application B, i am calling the action method as follow:-
try
{
using (WebClient wc = new WebClient())
{
string url = "https://localhost:44302/" + "Home/CreateResource";
Uri uri = new Uri(url);
wc.Headers.Add(HttpRequestHeader.ContentType, "application/json");
output = wc.UploadString(uri, data);
}
}
catch (WebException e)
{
}
List<CRUDOutput> result = JsonConvert.DeserializeObject<List< CRUDOutput>>(output);
but i will get the following exception when i tried to deserialize the output:-
Error converting value
"[{"operation":{"result":{"status":"Success","message":"Resource has
been added successfully to ......"},"name":"CREATE
RESOURCE"}},{"operation":{"result":{"status":"Failed","message":"Account
addition "},"name":"ADD ACCOUNTS"}}]" to type
'System.Collections.Generic.List`1[S.ViewModels.CRUDOutput]'. Path '',
line 1, position 464.
now the JSON return from web application A will be as follow:-
"\"[{\\\"operation\\\":{\\\"result\\\":{\\\"status\\\":\\\"Success\\\",\\\"message\\\":\\\"Resource 123 rfrf has been added successfully \\\"},\\\"name\\\":\\\"CREATE RESOURCE\\\"}},{\\\"operation\\\":{\\\"result\\\":{\\\"status\\\":\\\"Failed\\\",\\\"message\\\":\\\"Account addition \\\"},\\\"name\\\":\\\"ADD ACCOUNTS\\\"}}]\""
so can anyone advice why i am unable to deserialize to a list of objects?
The output as you've pasted is encoded as JSON twice. Compare the difference between:
"\"[{\\\"operation\\\":{\\\"result\\\":{\\\"status\\\":\\\"Success\\\",\\\"message\\\":\\\"Resource 123 rfrf has been added successfully \\\"},\\\"name\\\":\\\"CREATE RESOURCE\\\"}},{\\\"operation\\\":{\\\"result\\\":{\\\"status\\\":\\\"Failed\\\",\\\"message\\\":\\\"Account addition \\\"},\\\"name\\\":\\\"ADD ACCOUNTS\\\"}}]\""
and
"[{\"operation\":{\"result\":{\"status\":\"Success\",\"message\":\"Resource 123 rfrf has been added successfully \"},\"name\":\"CREATE RESOURCE\"}},{\"operation\":{\"result\":{\"status\":\"Failed\",\"message\":\"Account addition \"},\"name\":\"ADD ACCOUNTS\"}}]"
This happens because you're encoding the result as Json twice. Replace:
return Json(JsonConvert.SerializeObject(result));
with
return Json(result); // This encodes as JSON automatically
I am using http client to return a json response from a webservice. The example I am following here is from code project tutorial. However its example only returns into a var, it was created for the method to be called on screen I am changing it to be called from within a class. I have removed the webservice for security.
My Main question is how would I change this function to return a List of cinemas instead of the var variable I have a class created as such. I tried changing var into List but i noticed json.net handles this list so I need return the var as a known object instead I think?.
public class City
{
public string id { get; set; }
public string timing_title { get; set; }
}
public class Citys
{
public List<City> city { get; set; }
}
I just don't know what to do to convert this so it returns a list of citys for me to use in function.
This is a list of example json data returned.
{"city":[{"id":"5521","timing_title":"Lahore"},{"id":"5517","timing_title":"Karachi"},{"id":"5538","timing_title":"Islamabad"},{"id":"5535","timing_title":"Rawalpindi"},{"id":"5518","timing_title":"Hyderabad"},{"id":"5512","timing_title":"Faisalabad"},{"id":"8028","timing_title":"Gujranwala"},{"id":"8027","timing_title":"Gujrat"}]}
public async void GetCinemasList()
{
try
{
using (HttpClient client = new HttpClient())
{
client.BaseAddress = new Uri("webserviceurl");
var url = "index.php/webservice/upcoming_movie";
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.GetAsync(url);
if (response.IsSuccessStatusCode)
{
var data = response.Content.ReadAsStringAsync();
var cityData = JsonConvert.DeserializeObject<City>(data.Result.ToString());
}
}
}
catch (Exception ex)
{
// MessageBox.Show("Some Error Occured");
}
}
You have a string holding a JSON value.
You can parse and iterate through JSON values like this:
var data = "{\"city\":[{\"id\":\"5521\",\"timing_title\":\"Lahore\"},{\"id\":\"5517\",\"timing_title\":\"Karachi\"},{\"id\":\"5538\",\"timing_title\":\"Islamabad\"},{\"id\":\"5535\",\"timing_title\":\"Rawalpindi\"},{\"id\":\"5518\",\"timing_title\":\"Hyderabad\"},{\"id\":\"5512\",\"timing_title\":\"Faisalabad\"},{\"id\":\"8028\",\"timing_title\":\"Gujranwala\"},{\"id\":\"8027\",\"timing_title\":\"Gujrat\"}]}";
JsonObject rootObject;
if (JsonObject.TryParse(data, out rootObject))
{
JsonArray cityArray = rootObject.GetNamedArray("city");
foreach (var jsonValue in cityArray)
{
JsonObject cityObject = jsonValue.GetObject();
Debug.WriteLine(cityObject.GetNamedString("timing_title"));
}
}
else
{
// Invalid JSON data.
}
Output:
Lahore
Karachi
Islamabad
Rawalpindi
Hyderabad
Faisalabad
Gujranwala
Gujrat
Why do have this error on this part of the code ?
this part
var data = serializer.Deserialize<EmailTemplate>(httpRequest.Form["data"].ToString());
my procedure
public int UpdateEmailTemplate()
{
HttpResponseMessage result = null;
ObjectService uploadFile = new ObjectService();
List<ActiveUp.Net.Mail.Attachment> attachment = new List<ActiveUp.Net.Mail.Attachment>();
var httpRequest = HttpContext.Current.Request;
if (httpRequest.Form["data"] != null)
{
var serializer = new JavaScriptSerializer();
var data = serializer.Deserialize<EmailTemplate>(httpRequest.Form["data"].ToString());
if (httpRequest.Files.Count > 0)
{
var docfiles = new List<string>();
foreach (string file in httpRequest.Files)
{
MemoryStream target = new MemoryStream();
httpRequest.Files[file].InputStream.CopyTo(target);
uploadFile.AddObject(data.Id, "SU_ENTITY_MSG_TEMPLATE","", target.GetBuffer(), httpRequest.Files[file].FileName);
}
}
AdminService List = new AdminService();
return List.UpdateEmailTemplate(data);
}
MY class
public class EmailTemplate
{
public int Id;
public string TypeObject;
public int? idObject;
public string ObjectName;
public string IdTeam;
public string IdTask;
public string Team;
public string task;
public string Title;
public string Subject;
public string dataHtml;
public List<Objects> fileListRequest;
}
It's pretty plainly saying that the contents of:
httpRequest.Form["data"]
...is an array of some sort. Adding .ToString() will just return it's type name. Passing that to Deserialize is what's giving you the error, as Deserialize is expecting an array and just getting a string.
Try taling the .ToString() off - this may not work. If it doesn't you'll have to convert httpRequest.Form["data"] to what ever data type you've put into it (whuich you do not say).
I'm trying to deserialize a Facebook friend's Graph API call into a list of objects. The JSON object looks like:
{"data":[{"id":"518523721","name":"ftyft"},
{"id":"527032438","name":"ftyftyf"},
{"id":"527572047","name":"ftgft"},
{"id":"531141884","name":"ftftft"},
{"id":"532652067","name"...
List<EFacebook> facebooks = new JavaScriptSerializer().Deserialize<List<EFacebook>>(result);
It's not working, because the primitive object is invalid. How can I deserialize this?
You need to create a structure like this:
public class Friends
{
public List<FacebookFriend> data {get; set;}
}
public class FacebookFriend
{
public string id {get; set;}
public string name {get; set;}
}
Then you should be able to do:
Friends facebookFriends = new JavaScriptSerializer().Deserialize<Friends>(result);
The names of my classes are just an example. You should use proper names.
Adding a sample test:
string json =
#"{""data"":[{""id"":""518523721"",""name"":""ftyft""}, {""id"":""527032438"",""name"":""ftyftyf""}, {""id"":""527572047"",""name"":""ftgft""}, {""id"":""531141884"",""name"":""ftftft""}]}";
Friends facebookFriends = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<Friends>(json);
foreach(var item in facebookFriends.data)
{
Console.WriteLine("id: {0}, name: {1}", item.id, item.name);
}
Produces:
id: 518523721, name: ftyft
id: 527032438, name: ftyftyf
id: 527572047, name: ftgft
id: 531141884, name: ftftft
Sometimes I prefer dynamic objects:
public JsonResult GetJson()
{
string res;
WebClient client = new WebClient();
// Download string
string value = client.DownloadString("https://api.instagram.com/v1/users/000000000/media/recent/?client_id=clientId");
// Write values
res = value;
dynamic dyn = JsonConvert.DeserializeObject(res);
var lstInstagramObjects = new List<InstagramModel>();
foreach(var obj in dyn.data)
{
lstInstagramObjects.Add(new InstagramModel()
{
Link = (obj.link != null) ? obj.link.ToString() : "",
VideoUrl = (obj.videos != null) ? obj.videos.standard_resolution.url.ToString() : "",
CommentsCount = int.Parse(obj.comments.count.ToString()),
LikesCount = int.Parse(obj.likes.count.ToString()),
CreatedTime = new System.DateTime(1970, 1, 1, 0, 0, 0, 0).AddSeconds((double.Parse(obj.created_time.ToString()))),
ImageUrl = (obj.images != null) ? obj.images.standard_resolution.url.ToString() : "",
User = new InstagramModel.UserAccount()
{
username = obj.user.username,
website = obj.user.website,
profile_picture = obj.user.profile_picture,
full_name = obj.user.full_name,
bio = obj.user.bio,
id = obj.user.id
}
});
}
return Json(lstInstagramObjects, JsonRequestBehavior.AllowGet);
}
A great way to automatically generate these classes for you is to copy your JSON output and throw it in here:
http://json2csharp.com/
It will provide you with a starting point to touch up your classes for deserialization.
Very easily we can parse JSON content with the help of dictionary and JavaScriptSerializer. Here is the sample code by which I parse JSON content from an ashx file.
var jss = new JavaScriptSerializer();
string json = new StreamReader(context.Request.InputStream).ReadToEnd();
Dictionary<string, string> sData = jss.Deserialize<Dictionary<string, string>>(json);
string _Name = sData["Name"].ToString();
string _Subject = sData["Subject"].ToString();
string _Email = sData["Email"].ToString();
string _Details = sData["Details"].ToString();
Newtonsoft.JSON is a good solution for these kind of situations. Also Newtonsof.JSON is faster than others, such as JavaScriptSerializer, DataContractJsonSerializer.
In this sample, you can the following:
var jsonData = JObject.Parse("your JSON data here");
Then you can cast jsonData to JArray, and you can use a for loop to get data at each iteration.
Also, I want to add something:
for (int i = 0; (JArray)jsonData["data"].Count; i++)
{
var data = jsonData[i - 1];
}
Working with dynamic object and using Newtonsoft serialize is a good choice.
I agree with Icarus (would have commented if I could),
but instead of using a CustomObject class,
I would use a Dictionary (in case Facebook adds something).
private class MyFacebookClass
{
public IList<IDictionary<string, string>> data { get; set; }
}
or
private class MyFacebookClass
{
public IList<IDictionary<string, object>> data { get; set; }
}
Serialization:
// Convert an object to JSON string format
string jsonData = JsonConvert.SerializeObject(obj);
Response.Write(jsonData);
Deserialization::
To deserialize a dynamic object
string json = #"{
'Name': 'name',
'Description': 'des'
}";
var res = JsonConvert.DeserializeObject< dynamic>(json);
Response.Write(res.Name);
If you're using .NET Core 3.0, you can use System.Text.Json (which is now built-in) to deserialize JSON.
The first step is to create classes to model the JSON. There are many tools which can help with this, and some of the answers here list them.
Some options are http://json2csharp.com, http://app.quicktype.io, or use Visual Studio (menu Edit → Paste Special → Paste JSON as classes).
public class Person
{
public string Id { get; set; }
public string Name { get; set; }
}
public class Response
{
public List<Person> Data { get; set; }
}
Then you can deserialize using:
var people = JsonSerializer.Deserialize<Response>(json);
If you need to add settings, such as camelCase handling, then pass serializer settings into the deserializer like this:
var options = new JsonSerializerOptions() { PropertyNamingPolicy = JsonNamingPolicy.CamelCase };
var person = JsonSerializer.Deserialize<Response>(json, options);
You can use this extensions
public static class JsonExtensions
{
public static T ToObject<T>(this string jsonText)
{
return JsonConvert.DeserializeObject<T>(jsonText);
}
public static string ToJson<T>(this T obj)
{
return JsonConvert.SerializeObject(obj);
}
}
Here is another site that will help you with all the code you need as long as you have a correctly formated JSON string available:
https://app.quicktype.io/