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Xamarin picker not showing the date from the list

I have the following code:
<ContentPage.BindingContext>
<local:PisterosViewModel/>
</ContentPage.BindingContext>
<Picker x:Name="pck_Pisteros"
ItemDisplayBinding="{Binding PisteroN}"
ItemsSource="{Binding PisterosLista}"
SelectedItem="{Binding PisterosLista}"
Title="Seleccione el usuario..."/>
Then my Model:
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.Contracts;
using System.Text;
namespace ServLottery.Models
{
public class Pisteros
{
public string PisteroID { get; set; }
public string PisteroN { get; set; }
}
}
and the view model:
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
namespace ServLottery.Models
{
public class PisterosViewModel
{
public IList<Pisteros> PisterosLista { get; set; }
public PisterosViewModel()
{
try
{
PisterosLista = new ObservableCollection<Pisteros>();
GetPisteros();
}
catch (Exception ex)
{
throw ex;
}
}
private async void GetPisteros()
{
try
{
RestClient client = new RestClient();
var pist = await client.Get<Models.Pisteros>("https://servicentroapi.azurewebsites.net/api/Pisteros");
if (pist != null)
{
PisterosLista = pist;
}
}
catch (Exception ex)
{
throw ex;
}
}
}
}
I set an breakpoint in var pist and it does have the values, then Pisteros list seems to get the values too, and this is executed when the page load, so I don't understand what's the problem, but the picker never shows the options.

Welcome to SO !
It seems like BindingContext in Xaml can not deal with the dynamical data ,such API data from web server .
There is a workaround binding ItemSource dynamically by using coding in ContentPage , also can refer to this officail sample .
Therefore , adding code in Page.Xaml.cs as follow :
protected override async void OnAppearing()
{
pck_Pisteros.ItemsSource = await GetTasksAsync();
base.OnAppearing();
}
private async Task<List<Pisteros>> GetTasksAsync()
{
List<Pisteros> PisterosLista = new List<Pisteros>();
HttpClient client = new HttpClient();
Uri uri = new Uri(string.Format("https://servicentroapi.azurewebsites.net/api/Pisteros", string.Empty));
HttpResponseMessage response = await client.GetAsync(uri);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
PisterosLista = JsonConvert.DeserializeObject<List<Pisteros>>(content);
Console.WriteLine("content :: " + content);
Console.WriteLine("Data :: " + PisterosLista);
}
return PisterosLista;
}
Now it will show:

How can i receive json data on PHP file?

I am new in Xamarin and C# ,I want from my app to insert Books name and author to MySql database ,so I made class with name BooksInsert.cs:
using System;
using System.Collections.Generic;
using System.Text;
namespace NewTest.Model
{
class BooksInsert
{
public string book_name { get; set; }
public string book_auther { get; set; }
}
}
then another class with name WebHelper.cs for GET and POST :
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Linq;
using System.Net;
namespace NewTest.Model
{
class WebHelper
{
public string Post(Uri url, string value)
{
var request = HttpWebRequest.Create(url);
var byteData = Encoding.ASCII.GetBytes(value);
request.ContentType = "application/json";
request.Method = "POST";
try
{
using (var stream = request.GetRequestStream())
{
stream.Write(byteData, 0, byteData.Length);
}
var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
return responseString;
}
catch (WebException)
{
return null;
}
}
public string Get(Uri url)
{
var request = HttpWebRequest.Create(url);
request.ContentType = "application/json";
request.Method = "GET";
try
{
var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
return responseString;
}
catch (WebException)
{
return null;
}
}
}
}
in the adding page NewBookPage.xaml I have this contents :
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="NewTest.NewBookPage">
<ContentPage.Content>
<StackLayout>
<Entry x:Name="b_name" Placeholder="Name of Book"/>
<Entry x:Name="b_auther" Placeholder="auther of Book"/>
<Button Text="Save"
Clicked="Button_Clicked"/>
</StackLayout>
</ContentPage.Content>
</ContentPage>
and NewBookPage.xaml.cs :
using NewTest.Model;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace NewTest
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class NewBookPage : ContentPage
{
public NewBookPage()
{
InitializeComponent();
}
private void Button_Clicked(object sender, EventArgs e)
{
WebHelper webHelper = new WebHelper();
BooksInsert item = new BooksInsert();
item.book_name= b_name.Text;
item.book_auther = b_auther.Text;
string request = JsonConvert.SerializeObject(item);
Uri url = new Uri(string.Format("localhost/API/insert.php"));
string response = webHelper.Post(url, request);
if (response != null)
{
//Handle your reponse here
}
else
{
//No Response from the server
}
}
}
}
Now i don't know how to continue send json file to insert.php file and in insert.php how can i receive json data ,can any one help me?

Your Post method in WebHelper.cs is expecting an Uri entity as the first argument to be passed to HttpWebRequest.Create. But as the documentation states, it seems to expect a string as parameter, not an Uri class. Besides HttpWebRequest is obsolete and should not be used for new developments. MS states you should use HttpClient instead.
Try using WebRequest.Create instead as in this tutorial from MS: https://learn.microsoft.com/en-us/dotnet/framework/network-programming/how-to-request-data-using-the-webrequest-class.
WebRequest request = WebRequest.Create("http://localhost/API/insert.php");
If you change the Post method signature, then you don't need to use the Uri class in NewBookPage.xaml.cs, just send the URI as string to Post.

I don't know how it is correct ,but i tried simple way to insert data's to MySql database ,I just did this NewBookPage.xaml :
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="NewTest.NewBookPage">
<ContentPage.Content>
<StackLayout>
<Entry x:Name="b_name" Placeholder="Name of Book"/>
<Entry x:Name="b_auther" Placeholder="auther of Book"/>
<Button Text="Save"
Clicked="Button_Clicked"/>
<WebView x:Name="webView"
WidthRequest="1000"
HeightRequest="500"/>
</StackLayout>
</ContentPage.Content>
</ContentPage>
NewBookPage.xaml.cs :
using NewTest.Model;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace NewTest
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class NewBookPage : ContentPage
{
public NewBookPage()
{
InitializeComponent();
}
private void Button_Clicked(object sender, EventArgs e)
{
webView.Source = " https://Mywebsite/insert.php?bn=" + b_name.Text + "&ba=" + b_auther.Text;
}
}
}
insert.php
$bname=$_GET['bn'];
$bauthor=$_GET['ba'];
$query = "INSERT INTO books VALUES ('','$bname','$bauthor')";
mysqli_query($berikane,$query);
data inserted correctly ,how is this solution possible?

Finally I have sent Post data from Xamarin to PHP file and received it as post value :
private void Button_Clicked(object sender, EventArgs e)
{
using (var client = new WebClient())
{
var values = new NameValueCollection();
values["book_name"] = b_name.Text;
values["book_auther"] = b_auther.Text;
var response = client.UploadValues("https://MyWeb/insert.php", values);
var responseString = Encoding.Default.GetString(response);
if (response != null)
{
DisplayAlert("Success" ,"Data Inserted Successfully" ,"OK");
}
}
}

Post a message to slack from c# application

I am trying to post a message on the #general channel and this worked when was doing it through a console app but Now I am using MVC and the message doesn't seem to get posted. Also, earlier I was using the webhook URL and now I am using the access token that I have.
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
namespace SlackClient.Controllers
{
public class SlackClient
{
private readonly Uri _uri;
private readonly Encoding _encoding = new UTF8Encoding();
public SlackClient(string urlWithAccessToken)
{
_uri = new Uri(urlWithAccessToken);
}
//Post a message using simple strings
public void PostMessage(string text, string username = null, string channel = null)
{
Payload payload = new Payload()
{
Channel = channel,
Username = username,
Text = text
};
PostMessage(payload);
}
//Post a message using a Payload object
public void PostMessage(Payload payload)
{
string payloadJson = JsonConvert.SerializeObject(payload);
using (WebClient client = new WebClient())
{
NameValueCollection data = new NameValueCollection();
data["payload"] = payloadJson;
var response = client.UploadValues(_uri, "POST", data);
//The response text is usually "ok"
string responseText = _encoding.GetString(response);
}
}
}
//This class serializes into the Json payload required by Slack Incoming WebHooks
public class Payload
{
[JsonProperty("channel")]
public string Channel { get; set; }
[JsonProperty("username")]
public string Username { get; set; }
[JsonProperty("text")]
public string Text { get; set; }
}
}
And the other class is SlackClientTest.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace SlackClient.Controllers
{
public class SlackClientTest
{
void TestPostMessage()
{
string urlWithAccessToken = "https://srishti2604.slack.com/services/hooks/incoming-webhook?token=my-tokenHere.";
SlackClient client = new SlackClient(urlWithAccessToken);
client.PostMessage(username: "Mr. Torgue",
text: "THIS IS A TEST MESSAGE! SQUEEDLYBAMBLYFEEDLYMEEDLYMOWWWWWWWW!",
channel: "#general");
}
}
}
Could someone tell me what might me wrong?
My console app looks like this
SlackClient.cs
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
namespace SlackProject1
{
public class SlackCient
{
private readonly Uri _webhookUrl;
private readonly HttpClient _httpClient = new HttpClient();
public SlackCient(Uri webhookUrl)
{
_webhookUrl = webhookUrl;
}
public async Task<HttpResponseMessage> SendMessageAsync(string message,
string channel = null, string username = null)
{
var payload = new
{
text = message,
channel,
username,
};
var serializedPayload = JsonConvert.SerializeObject(payload);
var response = await _httpClient.PostAsync(_webhookUrl,
new StringContent(serializedPayload, Encoding.UTF8, "application/json"));
return response;
}
}
}
And the Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace SlackProject1
{
class Program
{
static void Main(string[] args)
{
Task.WaitAll(IntegrateWithSlackAsync());
}
private static async Task IntegrateWithSlackAsync()
{
var webhookUrl = new Uri("https://hooks.slack.com/services/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");
var slackClient = new SlackCient(webhookUrl);
while (true)
{
Console.Write("Type a message: ");
var message = Console.ReadLine();
var response = await slackClient.SendMessageAsync(message);
var isValid = response.IsSuccessStatusCode ? "valid" : "invalid";
Console.WriteLine($"Received {isValid} response.");
}
}
}
}

XML not being passed to WCF

I'm running some local test on a API, for some reason the data XML data is not making it to the API. rData.labelDetail is submitted to the API as null.
It almost appears as though I'm using the incorrect ContentType but I've tried application/xml and text/xml with no success.
Request:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.IO;
using System.Text;
public partial class TestAPI : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
WebRequest request = WebRequest.Create("http://localhost:56146/Packages.svc/auth");
request.Method = "POST";
string postData = "<?xml version='1.0' encoding='UTF-8'?><RequestData xmlns='http://www.labels.com/label'><details>Test|Second Part</details></RequestData>";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/xml";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
WebResponse response = request.GetResponse();
Console.WriteLine(((HttpWebResponse)response).StatusDescription);
dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
Console.WriteLine(responseFromServer);
reader.Close();
dataStream.Close();
response.Close();
}
}
Service
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
namespace XYZService
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IPackages" in both code and config file together.
[ServiceContract]
public interface IPackages
{
[OperationContract]
[WebInvoke(Method = "POST",
RequestFormat = WebMessageFormat.Xml,
ResponseFormat = WebMessageFormat.Xml,
BodyStyle = WebMessageBodyStyle.Bare,
UriTemplate = "auth")]
ResponseData Auth(RequestData rData);
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
namespace XYZService
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Packages" in code, svc and config file together.
// NOTE: In order to launch WCF Test Client for testing this service, please select Packages.svc or Packages.svc.cs at the Solution Explorer and start debugging.
public class Packages : IPackages
{
#region
public ResponseData Auth(RequestData rData)
{
var data = rData.labelDetail.Split('|'); //Keep getting error here
var response = new ResponseData
{
Name = data[0],
PackageID = data[1]
};
return response;
}
#endregion
}
[DataContract(Namespace = "http://www.labels.com/label")]
public class RequestData
{
[DataMember]
public string labelDetail { get; set; }
}
[DataContract]
public class ResponseData
{
[DataMember]
public string Name { get; set; }
[DataMember]
public string PackageID { get; set; }
}
}

You have an element name mismatch. In your XML request, your root element RequestData has a nested element named details:
string postData = "<?xml version='1.0' encoding='UTF-8'?><RequestData xmlns='http://www.labels.com/label'><details>Test|Second Part</details></RequestData>";
But in your data contract, the corresponding property is named labelDetail:
[DataContract(Namespace = "http://www.labels.com/label")]
public class RequestData
{
[DataMember] // Notice that "Name" is not set
public string labelDetail { get; set; }
}
You need to make the names match, for instance by doing:
[DataMember(Name="details")]
public string labelDetail { get; set; }

WebException when trying to use Bing Translate API

I'm attempting to translate some English text to Chinese using Bing Translate's API.
My code is essentially what was provided on MSDN, albeit with a few modifications.
using System;
using System.Text;
using System.Net;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.Web;
using System.ServiceModel.Channels;
using System.ServiceModel;
namespace AutoTranslate2
{
public class Translator
{
private string authToken;
public Translator(string clientId, string clientSecret)
{
AdmAccessToken admToken;
AdmAuthentication admAuth = new AdmAuthentication("clientId", "client secret");
admToken = admAuth.GetAccessToken();
DateTime tokenReceived = DateTime.Now;
this.authToken = "Bearer " + admToken.access_token;
}
public string TranslateMethod(
string text,
string inputLang = "en",
string outputLang = "zh-CHS", // Chinese, simplified ('zh-CHT' is traditional Chinese)
string inputType = "text/html",
string outputType = "general")
{
// Add TranslatorService as a service reference, Address:http://api.microsofttranslator.com/V2/Soap.svc
TranslatorService.LanguageServiceClient client = new TranslatorService.LanguageServiceClient();
//Set Authorization header before sending the request
HttpRequestMessageProperty httpRequestProperty = new HttpRequestMessageProperty();
httpRequestProperty.Method = "POST";
httpRequestProperty.Headers.Add("Authorization", this.authToken);
// Creates a block within which an OperationContext object is in scope.
string translationResult;
using (OperationContextScope scope = new OperationContextScope(client.InnerChannel))
{
OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = httpRequestProperty;
//Keep appId parameter blank as we are sending access token in authorization header.
translationResult = client.Translate("", "<p>" + text + "</p>", inputLang, outputLang, inputType, outputType);
}
return translationResult;
}
}
[DataContract]
public class AdmAccessToken
{
[DataMember]
public string access_token { get; set; }
[DataMember]
public string token_type { get; set; }
[DataMember]
public string expires_in { get; set; }
[DataMember]
public string scope { get; set; }
}
public class AdmAuthentication
{
public static readonly string DatamarketAccessUri = "https://datamarket.accesscontrol.windows.net/v2/OAuth2-13";
private string clientId;
private string clientSecret;
private string request;
public AdmAuthentication(string clientId, string clientSecret)
{
this.clientId = clientId;
this.clientSecret = clientSecret;
//If clientid or client secret has special characters, encode before sending request
this.request = string.Format("grant_type=client_credentials&client_id={0}&client_secret={1}&scope=http://api.microsofttranslator.com", HttpUtility.UrlEncode(clientId), HttpUtility.UrlEncode(clientSecret));
}
public AdmAccessToken GetAccessToken()
{
return HttpPost(DatamarketAccessUri, this.request);
}
private AdmAccessToken HttpPost(string DatamarketAccessUri, string requestDetails)
{
//Prepare OAuth request
WebRequest webRequest = WebRequest.Create(DatamarketAccessUri);
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.Method = "POST";
byte[] bytes = Encoding.ASCII.GetBytes(requestDetails);
webRequest.ContentLength = bytes.Length;
using (Stream outputStream = webRequest.GetRequestStream())
{
outputStream.Write(bytes, 0, bytes.Length);
}
WebResponse webResponse = webRequest.GetResponse();
using (webResponse)
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(AdmAccessToken));
//Get deserialized object from JSON stream
AdmAccessToken token = (AdmAccessToken)serializer.ReadObject(webResponse.GetResponseStream());
return token;
}
}
}
}
...and somewhere else in my code, I do...
Translator t = new Translator(client_id, secret);
string output = t.TranslateMethod(text);
However, the code always returns an exception:
Unhandled Exception: System.Net.WebException: The remote server returned an error: (400) Bad Request.
at System.Net.HttpWebRequest.GetResponse()
at AutoTranslate2.AdmAuthentication.HttpPost(String DatamarketAccessUri, String requestDetails) in C:\Users\Deflect\AutoTranslate2\AutoTranslate2\Translate.cs:line 102
at AutoTranslate2.AdmAuthentication.GetAccessToken() in C:\Users\Deflect\AutoTranslate2\AutoTranslate2\Translate.cs:line 87
at AutoTranslate2.Translator..ctor(String clientId, String clientSecret) in C:\Users\Deflect\AutoTranslate2\AutoTranslate2\Translate.cs:line 26
at AutoTranslate2.Chinese.Parse(String rawText) in C:\Users\Deflect\AutoTranslate2\AutoTranslate2\Parse.cs:line 68
at AutoTranslate2.Program.Main(String[] args) in C:\Users\Deflect\AutoTranslate2\AutoTranslate2\Program.cs:line 19
I'll be the first to admit I really don't know what my code is doing, since I mostly copied and pasted from MSDN -- does anybody know why my code is returning an exception, and how I can get it to work?

It was this line:
AdmAuthentication admAuth = new AdmAuthentication("clientId", "client secret");
I forgot to swap the strings in the examples with the actual variables.