I'm trying to figure out a bug in my C# Xamarin Android code. Simple thing this application is ought to do - connect to the REST API, download the contents as a string for further analysis. At first my mistake was not including async tasks and using voids instead, but when I changed them the code seems to be stuck at point of retrieval of data.
String content;
private void OnClick1(object sender, EventArgs e)
{
output.Text = "";
GetJSONTextFromWeb("https://ameobea.me/osutrack/api/get_changes.php?user=XXXXXX&mode=0", "XXXXXX", "0");
while (content==null)
{
DoNothing();
}
output.Text = content;
}
private async Task GetJSONTextFromWeb(String address, String user, String modeID)
{
URL url = new URL(address);
URLConnection conn = url.OpenConnection();
//conn.AddRequestProperty("user", user); those lines are
//conn.AddRequestProperty("mode", modeID); removed for investigation.
//conn.Connect(); //this one caused the same issue.
content = (String)conn.Content; //Here the code seems to freeze without any warning.
}
private void DoNothing()
{
//literally. Made to await for the result.
}
Anyone knows the possible reason?
I'd suggest swapping out the use of that particular library in favor of the System.Http assembly, it's supported in Xamarin and is a lot better documented. I'd change your above code to something like below (Don't forget to declare System.Net.Http in the same place that you've declared your other assemblies).
using System.Net.Http;
async private void OnClick1(object sender, EventArgs e)
{
output.Text = "";
// await the return of a string from the url address
// awaiting this removes the need for the pointless while loop you were doing
content = await GetJSONTextFromWeb("https://ameobea.me/osutrack/api/get_changes.php?user=XXXXXX&mode=0");
output.Text = content;
}
private async Task<string> GetJSONTextFromWeb(String address)
{
// The library you were using is a poorly documented port from a JAVA library
// I'd suggest using the http library, it's supported in Xamarin and has better docs
var client = new HttpClient();
var data = await client.GetStringAsync(address);
return data;
}
Related
First of all hello guys i just wanted to add button that downloads zip files from link and then unzips and i ran into problems i get this error:
"System.IO.IOException: 'The process cannot access the file
'C:\GTA\TEST.zip' because it is being used by another process.'"
It looks really simple but i can't solve it so i hope you guys help me. this is code:
private void button2_Click(object sender, EventArgs e)
{
string root = #"C:\GTA";
//this if directory doesn't exist
if (!Directory.Exists(root))
{
Directory.CreateDirectory(root);
}
progressBar1.Value = 0;
WebClient webcl = new WebClient();
webcl.DownloadFileCompleted += Webcl_DownloadFileCompleted;
webcl.DownloadProgressChanged += Webcl_DownloadProgressChanged;
webcl.DownloadFileAsync(new Uri("https://download1474.mediafire.com/17r5hin4vceg/izkb8vk7pudg5g4/TEST.zip"), #"C:\GTA\TEST.zip");
string targetfolder = #"C:\GTA\UNZIPEDFolder";
string sourceZipFile = #"C:\GTA\TEST.zip";
ZipFile.ExtractToDirectory(sourceZipFile, targetfolder);
}
I'm no expert here, however you get the file asynchronosly without awaiting it.
DownloadFileAsync
So you make a call to extract the file while it's being downloaded.
You calling ExtractToDirectory before file will be actually downloaded, as file downloading is async. So, you need to await when downloading process will finish. To do so, you will need the following
make the whole event click handler async - private async void button2_Click(object sender, EventArgs e).
replace DownloadFileAsync which returns void and thus is not async/await-friendly with DownloadFileTaskAsync, which is awaitable.
Then you will able to await downloading with await webcl.DownloadFileTaskAsync(...args here...);
finally, you can remove DownloadFileCompleted subscription, as you may be sure that after await the file downloading is completed.
By the way, WebClient is considered as an old API and is not recommended for using in the new code. You may consider to switch to HttpClient.
To elaborate a bit on the two previous answers, you are in fact trying to unzip the file before you have downloaded it. You should change your code as follows:
private async void button2_Click(object sender, EventArgs e)
{
string root = #"C:\GTA";
//this if directory doesn't exist
if (!Directory.Exists(root))
{
Directory.CreateDirectory(root);
}
progressBar1.Value = 0;
WebClient webcl = new WebClient();
webcl.DownloadFileCompleted += Webcl_DownloadFileCompleted;
webcl.DownloadProgressChanged += Webcl_DownloadProgressChanged;
await webcl.DownloadFileAsync(new Uri("https://download1474.mediafire.com/17r5hin4vceg/izkb8vk7pudg5g4/TEST.zip"), #"C:\GTA\TEST.zip");
string targetfolder = #"C:\GTA\UNZIPEDFolder";
string sourceZipFile = #"C:\GTA\TEST.zip";
ZipFile.ExtractToDirectory(sourceZipFile, targetfolder);
}
Note the async as well as the await before DownloadFileAsync().
Additionally, you might want to refactor that a bit and move the download / unzip part out of the Button Event Handler.
I have an trouble in C# program which using php scripts to translate words and download the result string into TextBox.
My program has two TextBoxes
txtWord, txtTranslatedWord
and that's the simplified code
WebClient c = new WebClient();
private void txtWord_TextChanged(object sender, EventArgs e)
{
string response = c.DownloadString("http://example.com/Services/Translator/lang/EnglishToArabic.php?Word=" + txtWord.Text);
switch (response.ToLower())
{
case "not exist":
{
txtTranslatedWord.Text = "{Sorry but no translation for this word!}";
break;
}
default:
{
txtTranslatedWord.Text = response;
break;
}
}
}
The problem its when the text is changed the program lagging and looks like it would Stopped Working.
The program worked successfully but after so much lagging ,
especially if the writer is writing so fast.
I tried BackgroundWorker and make an delay like when user stop writing for 2 second then program start to translate but still lagging without any luck.
Is there any easy way to do this without problems?
Try to use asynchrony.
WebClient does not support concurrent I/O operations, so will be use HttpClient.
HttpClient client = new HttpClient();
private async void txtWord_TextChanged(object sender, EventArgs e)
{
var response = await client.GetStringAsync(
"http://example.com/Services/Translator/lang/EnglishToArabic.php?Word=" + txtWord.Text);
switch (response.ToLower())
{
case "not exist":
{
txtTranslatedWord.Text = "{Sorry but no translation for this word!}";
break;
}
default:
{
txtTranslatedWord.Text = response;
break;
}
}
}
Your problem is that every character your user types into the textbox results in a WebClient download that has to complete before the next keypress can be accepted. I'd suggest you do the following...
Create a timer that starts or restarts each time the user enters a character and that when expires disables the textbox and runs the search before re-enabling the textbox. You'd also do well to use an asynchronous WebClient call.
I have created a very simple UWP application with a single button. Clicking it should show the built-in share popup to share a PDF file.
The fact is that I have it working for Windows 10 (Desktop) but it doesn't work for mobile (the popup doesn't appear on the screen).
The PDF file comes as a byte array (because it will come from a remote service).
This is the code in MainPage.xaml.cs
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
DataTransferManager.GetForCurrentView().DataRequested += OnDataRequested;
}
protected override async void OnNavigatedTo(NavigationEventArgs e)
{
// This should come from a service
PdfBytes = await Microsoft.Toolkit.Uwp.StorageFileHelper.ReadBytesFromPackagedFileAsync("Document.pdf");
}
public byte[] PdfBytes { get; set; }
private async void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
var deferral = args.Request.GetDeferral();
var si = await StorageFile.CreateStreamedFileAsync("Document.pdf", stream =>
{
var writeStream = stream.AsStreamForWrite();
writeStream.Write(PdfBytes, 0, PdfBytes.Length);
stream.Dispose();
}, null);
args.Request.Data.Properties.Title = "PDF Document";
args.Request.Data.Properties.Description = "Some description";
args.Request.Data.SetStorageItems(new IStorageItem[] { si });
deferral.Complete();
}
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
DataTransferManager.ShowShareUI();
}
}
Is it correct? If it's not, how should I share the PDF (from its bytes)?
Thank you for your feedback. It seems that CreateStreamedFileAsync method does not work properly with Share contract in Mobile. We've logged this issue internally and I will update here once there is any progress.
For now, as a workaround, you can store the file in TemporaryFolder first and then share it like the following:
private async void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
var deferral = args.Request.GetDeferral();
var tempFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync("Document.pdf", CreationCollisionOption.ReplaceExisting);
await FileIO.WriteBytesAsync(tempFile, PdfBytes);
args.Request.Data.Properties.Title = "PDF Document";
args.Request.Data.Properties.Description = "Some description";
args.Request.Data.SetStorageItems(new IStorageItem[] { tempFile });
deferral.Complete();
}
Temporary app data store is the right place for data that you don’t want persisted after the current app session. The system can delete data stored at this location as needed to free up space. You can use it for any intermediate or temporary files. If you are writing large amounts of data to Temp, it is a good idea to clear it when your app is initialized to avoid the system or the user having to take action to free up storage. And you can do this by calling:
await ApplicationData.ClearAsync(ApplicationDataLocality.Temporary);
You have similar issue I had I believe
Have you tried changing
private async void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
var deferral = args.Request.GetDeferral();
var si = await StorageFile.CreateStreamedFileAsync("Document.pdf", stream =>
{
var writeStream = stream.AsStreamForWrite();
writeStream.Write(PdfBytes, 0, PdfBytes.Length);
stream.Dispose();
args.Request.Data.Properties.Title = "PDF Document";
args.Request.Data.Properties.Description = "Some description";
args.Request.Data.SetStorageItems(new IStorageItem[] { si });
deferral.Complete();
}, null);
}
I havent checked this code, so it probably wont compile but I have found that I had issue that looks similar to yours, if threads are involved. Take look at my issue here UWP DataTransferManager ShowShareUI() Opens Sharing Dialog with "This app can't share right now" and Closes it Immediately After
I faced the same issue, My share worked good in desktop application but not in mobile. After big struggle I found that the deferral is not working in windows 10 mobile.
So better remove these lines and try. Its working
var deferral = args.Request.GetDeferral();
deferral.Complete();
I want use Telegram API in C# for send a simple message to a number. I found some lib's on GitHub but I am not able to use them.
Can anyone give a simple code ? Can I simply make HTTP calls ?
Install-Package Telegram.Bot
Create a bot using the botfather
get the api key using the /token command (still in botfather)
use this code:
var bot = new Api("your api key here");
var t = await bot.SendTextMessage("#channelname or chat_id", "text message");
You can now pass a channel username (in the format #channelusername)
in the place of chat_id in all methods (and instead of from_chat_id in
forwardMessage). For this to work, the bot must be an administrator in
the channel.
https://core.telegram.org/bots/api
Here is the easiest way I found so far. I found it here, thanks to Paolo Montalto https://medium.com/#xabaras/sending-a-message-to-a-telegram-channel-the-easy-way-eb0a0b32968
After creating a Telegram bot via BotFather and getting your destination IDs
via https://api.telegram.org/bot[YourApiToken]/getUpdates
you can send a message to your IDs by issuing an HTTP GET request to Telegram BOT API using the following URL https://api.telegram.org/bot[YourApiToken]/sendMessage?chat_id=[DestitationID]&text=[MESSAGE_TEXT]
Details on a simple way to create a bot and get IDs may be found here: https://programmingistheway.wordpress.com/2015/12/03/send-telegram-messages-from-c/
You can test those url strings even directly in browser.
Here is a simple method I use in C# to send messages, without dependency on any bot api related dll and async calls complication:
using System.Net;
...
public string TelegramSendMessage(string apilToken, string destID, string text)
{
string urlString = $"https://api.telegram.org/bot{apilToken}/sendMessage?chat_id={destID}&text={text}";
WebClient webclient = new WebClient();
return webclient.DownloadString(urlString);
}
use this code :)
with https://github.com/sochix/TLSharp
using TeleSharp.TL;
using TLSharp;
using TLSharp.Core;
namespace TelegramSend
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
TelegramClient client;
private async void button1_Click(object sender, EventArgs e)
{
client = new TelegramClient(<your api_id>, <your api_key>);
await client.ConnectAsync();
}
string hash;
private async void button2_Click(object sender, EventArgs e)
{
hash = await client.SendCodeRequestAsync(textBox1.Text);
//var code = "<code_from_telegram>"; // you can change code in debugger
}
private async void button3_Click(object sender, EventArgs e)
{
var user = await client.MakeAuthAsync(textBox1.Text, hash, textBox2.Text);
}
private async void button4_Click(object sender, EventArgs e)
{
//get available contacts
var result = await client.GetContactsAsync();
//find recipient in contacts
var user = result.users.lists
.Where(x => x.GetType() == typeof(TLUser))
.Cast<TLUser>()
.Where(x => x.first_name == "ZRX");
if (user.ToList().Count != 0)
{
foreach (var u in user)
{
if (u.phone.Contains("3965604"))
{
//send message
await client.SendMessageAsync(new TLInputPeerUser() { user_id = u.id }, textBox3.Text);
}
}
}
}
}}
There is now WTelegramClient, using the latest Telegram Client API protocol (connecting as a user, not bot).
The library is very complete but also very easy to use. Follow the README on GitHub for an easy introduction.
To send a message to someone can be as simple as:
using TL;
using var client = new WTelegram.Client(); // or Client(Environment.GetEnvironmentVariable)
await client.LoginUserIfNeeded();
var result = await client.Contacts_ResolveUsername("USERNAME");
await client.SendMessageAsync(result.User, "Hello");
//or by phone number:
//var result = await client.Contacts_ImportContacts(new[] { new InputPhoneContact { phone = "+PHONENUMBER" } });
//client.SendMessageAsync(result.users[result.imported[0].user_id], "Hello");
1-first create a channel in telegram (for example #mychanel)
2-create a telegram bot (for example #myTestBot) and get api token for next step
3-add #myTestBot to your channel(#mychanel) as administrator user
4-use below code for send message:
var bot = new TelegramBotClient("api_token_bot");
var s = await bot.SendTextMessageAsync("#mychanel", "your_message");
this code work for me:
using System.Net;
public class TelegramBot
{
static readonly string token = "123456789:AAHsxzvZLfFAsfAY3f78b8t6MXw3";
static readonly string chatId = "123456789";
public static string SendMessage(string message)
{
string retval = string.Empty;
string url = $"https://api.telegram.org/bot{token}/sendMessage?chat_id={chatId}&text={message}";
using(var webClient = new WebClient())
{
retval = webClient.DownloadString(url);
}
return retval;
}
}
I've written a client library for accessing Telegram bot's API and its source code is available in the Github. You can browse to the Telebot.cs file to see a sample of how to send a message to the bot API.
Github URL: github.com/mrtaikandi/Telebot
Nuget URL: nuget.org/packages/Telebot
Same unexplicable errors.
Solution: elevate the framework dastination to minimum 4.6; errors disappear.
Perhaps official support pages at
https://telegrambots.github.io/book/1/quickstart.html
are a little bit confusing saying: "...a .NET project targeting versions 4.5+"
bye
Just look and learn how to make a POST HTTP request with your favorite language.
Then learn how to use Telegram Bot API with the documentation:
https://core.telegram.org/bots
https://core.telegram.org/bots/api
hi there :) il get right to it.
Problem :
when i try to instanciate LiveConnectClient and then try to access the event : GetCompleted
which supose to be in the LiveConnectClient is not showing and on all the examples i been looking at even those on here are using it. this is not the only class this is happening on it is also happening on LiveAuthClient as well no events even the post on the net says there should be.
i tried to reinstall Vs2012 and sdk wp8 and live sdk from scratch but have not solved it
for refrence i using this example to see if i can it to work :
//event triggered when Skydrive sign in status is changed
private void btnSignIn_SessionChanged(object sender, Microsoft.Live.Controls.LiveConnectSessionChangedEventArgs e)
{
//if the user is signed in
if (e.Status == LiveConnectSessionStatus.Connected)
{
session = e.Session;
client = new LiveConnectClient(e.Session);
infoTextBlock.Text = "Accessing SkyDrive...";
//get the folders in their skydrive
client.GetCompleted +=
new EventHandler<LiveOperationCompletedEventArgs>(btnSignin_GetCompleted);
client.GetAsync("me/skydrive/files?filter=folders,albums");
}
//otherwise the user isn't signed in
else
{
infoTextBlock.Text = "Not signed in.";
client = null;
}
}
i got no luck solving it and running out of ideas. So im hoping one of u boys out there can shed some light on it or lend a hand with dew wise words :)
thanks in advance. and i do apologies if this is to long a post.
regards jens
Indeed, it seems like those events have been removed in the latest versions of the SDK. You don't need them though, thanks to the async/await keywords. First, mark your method as async, then call the GetAsync method with the await keyword. And place afterward the code you would normally put in the GetCompleted event:
private async void btnSignIn_SessionChanged(object sender, Microsoft.Live.Controls.LiveConnectSessionChangedEventArgs e)
{
//if the user is signed in
if (e.Status == LiveConnectSessionStatus.Connected)
{
session = e.Session;
client = new LiveConnectClient(e.Session);
infoTextBlock.Text = "Accessing SkyDrive...";
//get the folders in their skydrive
var result = await client.GetAsync("me/skydrive/files?filter=folders,albums");
// Do here what you would normally do in btnSignin_GetCompleted
}
//otherwise the user isn't signed in
else
{
infoTextBlock.Text = "Not signed in.";
client = null;
}
}