I am new to JSON strings so I am having a hard time with it.
I am used to SOAP Web Services where in Visual Studio automatically creates the strongly typed Classes for me in the background.
JSON - REST Web Services are for me is much tedious as I have to create manually the equivalent Strongly Typed Classes. (Or I maybe wrong).
I have this JSON String being returned to me by a REST Web Service:
{"Message":"The request is invalid.","ModelState":{"command":["Required property 'Vendor' not found in JSON. Path '', line 1, position 310."],"command.Terms":["The Terms field is required."]}}
Could you guide me on the equivalent Class?
Appreciate your help!
Regards,
Jake
assuming you are using JSON.NET...
Public Class Response
Public Property Message As String
Public Property ModelState As ModelState
End Class
Public Class ModelState
<JsonProperty("command")>
Public Property Command As List(Of String) = New List(Of String)
<JsonProperty("command.Terms")>
Public Property Terms As List(Of String) = New List(Of String)
End Class
Usage:
Dim response As Response = JsonConvert.DeserializeObject(jsonString)
Related
I’m on the way to implement an interface to the Ameritrade Rest API in a vb.net application (with httpclient).
Amongst other things, I have to query quotes from a ticker list (e.g. AMD,MSFT,AMZN, ....).
The call of the API works without problems, I get a valid Json back, but the Json is not given back in a way, I would expect.
I now search the best way to handle that problem...
This is not the first interface to a Rest API, I have implemented.
Normally, I implement a corresponding data class in vb.net and then use JsonConvert (from Newtonsoft) to deserialize the Json string into my data class.
Example:
Dim oObject As New DataClass
oObject = JsonConvert.DeserializeObject(Of DataClass)(JsonString)
whereby DataClass is the vb.net class that is defined according to the data in the Json string.
Problem:
The ticker symbol-list to query is dynamic and can change from api call to api call.
If I - e.g. - query AMD and MSFT in a call, I get back (cut to only a few fields) the following Json:
{
"AMD": {
"assetType": "EQUITY",
"symbol": "AMD",
"description": "Advanced Micro Devices, Inc. - Common Stock",
"bidPrice": 92.11
},
"MSFT": {
"assetType": "EQUITY",
"symbol": "MSFT",
"description": "Microsoft Corporation - Common Stock",
"bidPrice": 243.1
}
}
To be able to deserialize the Json, I would have to implement the following DataClass:
Public Class DataClass
Public Property AMD As AMD
Public Property MSFT As MSFT
End Class
Public Class AMD
Public Property assetType As String
Public Property symbol As String
Public Property description As String
Public Property bidPrice As Double
End Class
Public Class MSFT
Public Property assetType As String
Public Property symbol As String
Public Property description As String
Public Property bidPrice As Double
End Class
This would work but is absolutely static and does not make any sense, as I would have to implement a (identical) class for any ticker, I maybe want to query in the feature.
I would expect to get back a dynamic list so that I could implement the class as following:
Public Class DataClass
Public Property TickerDetails As List(Of TickerDetail)
End Class
Public Class TickerDetail
Public Property assetType As String
Public Property symbol As String
Public Property description As String
Public Property bidPrice As Double
End Class
This way, I would be able to deserialize in a List of TickerDetails and the go thru the list (no matter, which symbols I queried).
But, I can’t change, what I get back over the API...
Question:
What is the best way to handle this problem?
You should create a class to represent the a generic stock and then use DeserializeObject to deserialize it into a Dictionary(Of String, [classname]) where the Key represents the stock symbol and the value represents the class.
Take a look at this example:
Public Class Stock
Public Property assetType As String
Public Property symbol As String
Public Property description As String
Public Property bidPrice As Double
End Class
'...
Dim stocks = JsonConvert.DeserializeObject(Of Dictionary(Of String, Stock))(response)
Example: Live Demo
First thanks for the comments.
I ended up to do it completely different now...
I had further problems with the Ameritrade API:
Some fields are named with leading numbers (52WkHigh and 52WkLow) and
vb.net dev's know, that VB.net don't like properties in classes that
are named with a leading number
So I had to "patch" the received Json data and change the names on the fly to other names ("52WkHigh" to "dble52WkHigh" and "52WkLow" to "dble52WkLow") to be able to deserialize
over the data class, what is not nice
Further, I finally need the data (as fast as possible) in a data table and had "a long way to go":
get data -> deserialize to the data class -> walk thru the data class and overtake the data in the data table.
So.. my new solution (with JObject):
Note: needs:
Imports Newtonsoft.Json.Linq
Code snippets:
Create data table in memory:
Dim dtErgebnis As New DataTable
Dim drTemp As DataRow
With dtErgebnis.Columns
.Add("symbol", System.Type.GetType("System.String"))
.Add("lastPrice", System.Type.GetType("System.Double"))
.Add("lastSize", System.Type.GetType("System.Int32"))
.Add("quoteTime", System.Type.GetType("System.DateTime")) ' Note: is a Long in Json
...
End With
Parse the Json-String and fill the datatable:
get the data over httpclient (in JsonString)...
Dim oJson As JObject = JObject.Parse(JsonString) ' creates children tokens
Dim results As List(Of JToken) = oJson.Children().ToList
For Each item As JProperty In results
item.CreateReader()
drTemp = dtErgebnis.NewRow() ' create a new row to data table in memory
' Fill the fields
drTemp("symbol") = item.Value("symbol")
drTemp("lastPrice") = item.Value("lastPrice")
drTemp("lastSize") = item.Value("lastSize")
drTemp("quoteTime") = GetUTCDateFromTimeStamp(item.Value("quoteTimeInLong")).AddHours(1) ' original Long
...
' Add the new row to the data table
dtErgebnis.Rows.Add(drTemp)
' Save the changes
dtErgebnis.AcceptChanges()
Next
Additional note: The Ameritrade API gives back the time stamps as long (additional hurdle), but I (and I think also you;-) want it as datetime.
Therefore the Long (I think this data type comes from Java/Unix) has to be "translated" to datetime = vb.net function GetUTCDateFromTimeStamp below:
Public Function GetUTCDateFromTimeStamp(TimeStamp As Long) As DateTime
Static startTime As New DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)
Return startTime.AddMilliseconds(TimeStamp)
End Function
Additional note:
As I want to have the Swiss time, I add one hour to the UTC time.
So.. this a real good solution for me (exactly for the Ameritrade API).
And.. it's blazing fast... (I get 19 tickers with all fields and show the result (data table) in a data grid).
All together took < 1 Second ("felt" about 500 ms)
Hope this helps somebody...
I am building a program in Visual Studio 2017 in Windows Forms - sorry but that's the only thing I know how to use - anyway, most everything for this is C#, so I've been having trouble getting help.
I have translated the Microsoft provided example for a C# program to connect to Azure Cognitive Translation services, signed up, got all my keys, etc.
When I run the code, I get the following error:
Newtonsoft.Json.JsonSerializationException:
'Cannot deserialize the
current JSON object (e.g. {"name":"value"}) into type
System.Collections.Generic.List1[System.Collections.Generic.Dictionary2[System.String,System.Collections.Generic.List1[System.Collections.Generic.Dictionary2[System.String,System.String]]]]'
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 'error', line 1, position 9.'
I have tried too many things to list from many different sources. I do not know a whole lot about JSON and am asking for help with the code to solve the above issue.
Public Class DetectedLanguage
Public Property language As String
Public Property score As Double
End Class
Public Class Translation
Public Property text As String
Public Property two As String
End Class
Public Class Example
Public Property detectedLanguage As DetectedLanguage
Public Property translations As Translation()
End Class
Dim textToTranslate As String = root
Dim fromLanguage As String
Dim fromLanguageCode As String = cabbr
Dim toLanguageCode As String = "en"
Dim endpoint As String = String.Format(TEXT_TRANSLATION_API_ENDPOINT, "translate")
Dim uri As String = String.Format(endpoint & "&from={0}&to={1}", fromLanguageCode, toLanguageCode)
Dim body As System.Object() = New System.Object() {New With {Key .Text = textToTranslate}}
Dim requestBody = JsonConvert.SerializeObject(body)
Using client = New HttpClient()
Using request = New HttpRequestMessage()
request.Method = HttpMethod.Post
request.RequestUri = New Uri(uri)
request.Content = New StringContent(requestBody, Encoding.UTF8, "application/json")
request.Headers.Add("Ocp-Apim-Subscription-Key", COGNITIVE_SERVICES_KEY)
request.Headers.Add("Ocp-Apim-Subscription-Region", "westus")
request.Headers.Add("X-ClientTraceId", Guid.NewGuid().ToString())
Dim response = client.SendAsync(request).Result
Dim responseBody = response.Content.ReadAsStringAsync().Result
Dim result = JsonConvert.DeserializeObject(Of List(Of Dictionary(Of String, List(Of Dictionary(Of String, String)))))(responseBody)
Dim translation = result(0)("translations")(0)("text")
rtRoot.Text = translation
End Using
End Using
I have already used the jsonutil site to paste my JSON code in and get the classes.
Here is my JSON content:
[
{
"detectedLanguage":{
"language":"nl",
"score":1.0
},
"translations":[
{
"text":"bord vervangen en uitvoerig getest",
"to":"nl"
},
{
"text":"Board replaced and tested extensively",
"to":"en"
}
]
}
]
OK!!! after playing around with this - Jimi - your solution worked!!! thank you SO much! i had to remove the following to lines: request.Headers.Add("Ocp-Apim-Subscription-Region", "westus") request.Headers.Add("X-ClientTraceId", Guid.NewGuid().ToString())
Currently i get an error on a binding. The situation is that i write my settings to a JSON file. When the app opens again the JSON file is read and used throughout the application. Now there's a strange thing: When i bind a double value to the value of a nummericupdown than i get an error: type 'JValue' to type 'System.Nullable1[System.Double]'for 'en-US' however this error doesn't occur when i recreate the JSON list and file. (simply said when i delete the file and restart the app it will create a new instance of a class en write it to disk)
Property in class:
Public Property SomeValue As Double
Write/Reader JSON:
'Write
Using _file As StreamWriter = New StreamWriter(SettingFilePath)
Dim serializer As New JsonSerializer()
serializer.Formatting = Formatting.Indented
serializer.Serialize(_file, Me)
End Using
'Read
Return JsonConvert.DeserializeObject(Of Settings)(File.ReadAllText(settingsfile))
JSON string:
"SomeValue": 1.0,
Binding in XAML:
<Controls:NumericUpDown
Width="200"
HorizontalAlignment="Center"
Maximum="5"
Minimum="1"
NumericInputMode="All"
Speedup="false"
Value="{Binding SomeValue}" />
Please note that i use the Mathapps Metro nummericupdown control version 1.6.5
Newtonsoft version 10.0.0.1 (Cannot update due to dependencies)
Edit:
As asked i digged deeper and now know where it starts, but don't know yet how to resolve it. Is start with my class for example:
Public class Hello
Dim a as Object
Dim b as EnumTypeOfObjectIn_A
Dim SomeOtherStuff as String
End class
Now when i DeserializeObject de file to the Class Hello then variable a becomes a object of type JObject and this is why alot of logica afterwords goes wrong. When i create the object in code everything goes well because the TypeOf object matches the one i put in. So is there a work arround for the Deserializer to convert the object to the one that is indicated in variable b ?
Found the solution i was looking for. The Newtonsoft JSON contains the JsonSerializerSettings class that helps the de/serialization process. For me it is important to add the Type of object when serializing so that's exactly what TypeNameHandling and TypeNameAssemblyFormatHandling is for in the Newtonsoft JSON assembly
I ended up with this code:
Public Class Hello
Public Property A As Object
Dim settingsfile As String = "C:\jsontest.json"
Public Sub Save()
Using _file As StreamWriter = New StreamWriter(settingsfile)
_file.Write(JsonConvert.SerializeObject(Me, Formatting.Indented, New JsonSerializerSettings() With {
.TypeNameHandling = TypeNameHandling.Objects,
.TypeNameAssemblyFormatHandling = TypeNameAssemblyFormatHandling.Simple
}))
End Using
End Sub
Public Function Load() As Hello
Return JsonConvert.DeserializeObject(Of Hello)(File.ReadAllText(settingsfile), New JsonSerializerSettings() With {.TypeNameHandling = TypeNameHandling.Objects})
End Function
End Class
Public Class Person
Public Property Name As String
Public Property Age As Integer
Sub New()
Me.Name = "John"
Me.Age = 130
End Sub
End Class
Producing this JSON output, note the $Type
{
"$type": "MyNamespace.Hello, MyNamespace",
"A": {
"$type": "MyNamespace.Person, MyNamespace",
"Name": "John",
"Age": 130
}
}
I have a very simple application that I am using to learn move about MVC. In that application I search some data and return a JSON string that I want to use as the model for the view. I just can't seem to figure out how to get the view to consume the JSON as a set of data for it to show on screen.
The code I have so far:
Function Find(term As String) As ActionResult
Dim model As String = SearchData(term)
Return View(model)
End Function
SearchData returns a JSON string that can have one or many objects in it.
How do I now take the JSON returned from SearchData and use it in a view? In fact, when I attempt to add a view it wants to know what model to use. How do i also specific that?
Create a strongly typed object to store you data when parsed
Public Class Data
Public Property ID As Integer
Public Property Term As String
Public Property SomeProperty As String
Public Property SomeOtherProperty As String
End Class
Using a library like JSON.Net, parse the JSON returned from the search.
This assumes a collection of Data is returned from the search.
Imports Newtonsoft.Json;
Function Find(term As String) As ActionResult
Dim json As String = SearchData(term)
Dim model As List(Of Data) = JsonConvert.DeserializeObject(Of List(Of Data))(json)
Return View(model)
End Function
Let the view know to expect the strongly typed model.
#ModelType List(Of Data)
#Code
ViewData("Title") = "Find"
End Code
<h2>MyView</h2>
<!-- rest of view where model can be accessed -->
I'm using JSon.net to deserialize a json object i'm getting from the GravityForms Web API.
The json that I get back is this...
{"status":200,"response":{
"12":{"id":"12","title":"Test Form","entries":"1"},
"1":{"id":"1","title":"What's My Home Worth?","entries":"92"}
}
}
My VB.net Object that I'm deserializing into is
Namespace Forms
Public Class GFForm
Public Property id As String
Public Property title As String
Public Property entries As String
End Class
Public Class Response
<JsonProperty("1")>
Public Property GFForms() As GFForm
End Class
Public Class TopLevel
Public Property status As Integer
Public Property response As Response
End Class
End Namespace
and I am executing the JsonConvert statement like this..
Dim obj As GravityForms.Forms.TopLevel
obj = JsonConvert.DeserializeObject(Of GravityForms.Forms.TopLevel)(str)
It seems to successfully deserialize the json into my vb object but I am only getting 1 response object. I should be getting 2 of them right?
The odd thing is that the GFForm that I'm getting is the second one (ID:1), which makes it seem like it's over writing the value of the first object (ID:12).
Any help would be great because I've been messing with this for the better part of 2 days and I'm lost.
Edit:
This was not clear in my question above. I do not know the number of GFForm objects that I get back from the web service. It could be 2 (like in the example) or it could be 32 or 45 or whatever.
I'd like to put the GFForm objects in something I can bind to a datagridview
You have two GFForm properties in your response, but one Response object with one property to fill. Maybe you should try using something like that
Namespace Forms
Public Class GFForm
Public Property id As String
Public Property title As String
Public Property entries As String
End Class
Public Class Response
<JsonProperty("1")>
Public Property GFForms1 As GFForm
Public Property GFForms12 As GFForm
End Class
Public Class TopLevel
Public Property status As Integer
Public Property response As Response
End Class
End Namespace
EDIT: If you don't know the number of response properties, try creating a new Response object for each property.