I write a WPF Programm which reads the configuration of the PC.
The Programm has to be refreshed an the HttpWebRequest will delay the code so the UI will freez.
I tried to work with async / await tasks.
Method in Class Network:
public TreeView CreatTVURLs()
{
TreeView TVURLs = new TreeView(); //Here it will break. Says no STA-Thread
List<CPingables> lURLs = new List<CPingables>();
lURLs = ReadURLsFromFile();
TVURLs.Name = "URLs";
TVURLs.Background = System.Windows.Media.Brushes.Transparent;
TVURLs.BorderThickness = new Thickness(0);
foreach (CPingables item in lURLs)
{
tviURL.Items.Add("IP:\t\t\t" + item.IP.ToString());
tviURL.Items.Add("URL:\t\t\t" + item.URL);
... more stuff
Tried with Thread:
Code in MainWindow:
public async void openWindow()
{
TreeView tvURLs = new TreeView();
tvURLs = (TreeView) TreeViewTest();
//tvURLs = Network.CreatTVURLs();
StackPanel.Children.Add(tvURLs);
}
private TreeView TreeViewTest()
{
TreeView tvURLs = new TreeView();
Thread t = new Thread(() => { tvURLs = Network.CreatTVURLs(); });
t.SetApartmentState(ApartmentState.STA);
t.Start();
t.Join();
return tvURLs;
}
Tried with Task:
public async void openWindow()
{
TreeView tvURLs = new TreeView();
tvURLs = (TreeView) await TreeViewTest();
Task.WaitAll();
StackPanel.Children.Add(tvURLs);
}
private Task<TreeView> TreeViewTest()
{
TreeView tv = new TreeView();
return Task.Factory.StartNew(() => { tv=(TreeView)Network.CreatTVURLs()});
}
I get always says it must me a STA Thread to handle Formitems.
Edit:
HttpWebRequest
public async void pingIP()
{
try
{
if (_IPPingAvailible == true)
{
Ping pinger = new Ping();
PingReply replyIP = pinger.Send(_IP);
_PingByIP = replyIP.Status == IPStatus.Success;
}
}
catch (Exception)
{
_PingByIP = false;
}
try
{
if (_UrlAvailible == true)
{
var uriBuilder = new UriBuilder(_URL);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uriBuilder.Uri);
request.Timeout = 1000;
using (var response = await request.GetResponseAsync() as HttpWebResponse)
{
if (response != null && response.StatusCode == HttpStatusCode.OK)
{
_ReachableByHttp = true;
}
else
{
_ReachableByHttp = false;
}
}
}
}
catch
{
_ReachableByHttp = false;
}
}
The rule is, that you can access UI elements only in UI thread (called also Dispatcher thread, or main thread). You are breaking this rule. You have cerate new thread by:
Task.Factory.StartNew(...) resp by new Thread(...);, but you are manipulating the UI elements (treeview) inside the new thread.
Instead, you should perform only the I/O operation or HttpRequest/Response in the new thread, but everything else (e.g. creating treeview from the http response data) should be done in UI thread.
public async void openWindow()
{
TreeView tvURLs = await Network.CreatTVURLsAsync();
StackPanel.Children.Add(tvURLs);
}
public async Task<TreeView> CreatTVURLsAsync()
{
//you are in dispatcher thread here, so you can access UI elements here
TreeView TVURLs = new TreeView();
TVURLs.Name = "URLs";
TVURLs.Background = System.Windows.Media.Brushes.Transparent;
TVURLs.BorderThickness = new Thickness(0);
List<CPingables> lURLs = null;
await Task.Run(() =>
{
//you are in new thread now, so you cannot access UI elements here
lURL = ReadURLsFromFile();
});
//you are in dispatcher thread again, so you can access UI elements again
foreach (CPingables item in lURLs)
{
var tviURL = new TreeViewItem();
..more stuff
TVURLs.Items.Add(tviURL);
}
}
Related
i have the following ui -
For each line connection to crm should be tested. This is done in separate thread.
The test status of the connection to crm system is then updated in last column.
The problem is that the ui is only partly reponsive during threads run and updating of the ui, i.e.
i would like to click through the lines whilst updating.
Here is my code:
private async void btnTestAllConnections_Click(object sender, EventArgs e)
{
await TestConnectionsAsync();
}
private async Task TestConnectionsAsync()
{
try
{
int idxConn = columnLookup[ColumnIndex.Connection].Index;
if (lvInitParameters.Items.Count == 0)
return;
ManagedConnection connection = null;
btnTestAllConnections.Visible = false;
btnTestConnection.Visible = false;
panel2.Enabled = false;
panel3.Enabled = false;
tableLayoutPanel1.Enabled = false;
btnCancelTest.Visible = true;
List<Task> tasks = new List<Task>();
var cts = new CancellationTokenSource();
CancellationToken token = cts.Token;
foreach (ListViewItem lvi in lvInitParameters.Items)
{
InitParamProxy currentProfile = (InitParamProxy)lvi.Tag;
lvi.SubItems[idxConn].Text = "Testing...";
Task<bool> result =null;
try
{
result = Task.Run(
() =>
{
try
{
connection = currentProfile.ManagedConnection;
return connection?.ConnectionSuccess ?? false;
}
catch (Exception ex)
{
// crm exception
return false;
}
}, token);
if (token.IsCancellationRequested)
{
Console.WriteLine("\nCancellation requested in continuation...\n");
token.ThrowIfCancellationRequested();
}
ListViewItem testItem =
items.Where(si => ((InitParamProxy)lvi.Tag).ProfileKey.Equals(((InitParamProxy)si.Tag).ProfileKey)).SingleOrDefault();
lvi.SubItems[idxConn].Text = (result.Result) ? "Success" : "Fail";
if (testItem != null)
testItem.SubItems[idxConn].Text = (result.Result) ? "Success" : "Fail";
}
catch
{
ListViewItem testItem =
items.Where(si => ((InitParamProxy)lvi.Tag).ProfileKey.Equals(((InitParamProxy)si.Tag).ProfileKey)).SingleOrDefault();
lvi.SubItems[idxConn].Text = "Canceled";
if (testItem != null)
testItem.SubItems[idxConn].Text = "Canceled";
}
tasks.Add(result);
}
Task.WaitAll(tasks.ToArray());
btnTestAllConnections.Visible = true;
btnTestConnection.Visible = true;
panel2.Enabled = true;
panel3.Enabled = true;
tableLayoutPanel1.Enabled = true;
btnCancelTest.Visible = false;
}
catch (Exception)
{
}
}
In the end of your method you have
Task.WaitAll(tasks.ToArray());
This will block until all tasks are done. You should instead use WhenAll
await Task.WhenAll(tasks.ToArray());
You are also using result.Result in several places, and this also blocks. This should be replaced by awaiting the task, i.e. await result
First of all, sorry because I am so new at C# and I decided to make this question because I have been choked in this for hours.
I have an GUI that works with Google Cloud Speech services and make a Speech-to-Text operation. I share with you the whole method that runs when a button is clicked:
private async Task<object> StreamingMicRecognizeAsync(int seconds)
{
if (NAudio.Wave.WaveIn.DeviceCount < 1)
{
Console.WriteLine("No microphone!");
return -1;
}
GoogleCredential googleCredential;
using (Stream m = new FileStream(#"..\..\credentials.json", FileMode.Open))
googleCredential = GoogleCredential.FromStream(m);
var channel = new Grpc.Core.Channel(SpeechClient.DefaultEndpoint.Host,
googleCredential.ToChannelCredentials());
var speech = SpeechClient.Create(channel);
var streamingCall = speech.StreamingRecognize();
// Write the initial request with the config.
await streamingCall.WriteAsync(
new StreamingRecognizeRequest()
{
StreamingConfig = new StreamingRecognitionConfig()
{
Config = new RecognitionConfig()
{
Encoding =
RecognitionConfig.Types.AudioEncoding.Linear16,
SampleRateHertz = 48000,
LanguageCode = "es-ES",
},
InterimResults = true,
}
});
// Read from the microphone and stream to API.
object writeLock = new object();
bool writeMore = true;
var waveIn = new NAudio.Wave.WaveInEvent();
waveIn.DeviceNumber = 0;
waveIn.WaveFormat = new NAudio.Wave.WaveFormat(48000, 1);
waveIn.DataAvailable +=
(object sender, NAudio.Wave.WaveInEventArgs args) =>
{
lock (writeLock)
{
if (!writeMore) return;
streamingCall.WriteAsync(
new StreamingRecognizeRequest()
{
AudioContent = Google.Protobuf.ByteString
.CopyFrom(args.Buffer, 0, args.BytesRecorded)
}).Wait();
}
};
// Print responses as they arrive.
Task printResponses = Task.Run(async () =>
{
while (await streamingCall.ResponseStream.MoveNext(default(CancellationToken)))
{
foreach (var result in streamingCall.ResponseStream
.Current.Results)
{
foreach (var alternative in result.Alternatives)
{
Console.WriteLine(alternative.Transcript);
//Textbox1.Text = alternative.Transcript;
}
}
}
});
waveIn.StartRecording();
Console.WriteLine("Speak now.");
Result_Tone.Text = "Speak now:\n\n";
await Task.Delay(TimeSpan.FromSeconds(seconds));
// Stop recording and shut down.
waveIn.StopRecording();
lock (writeLock) writeMore = false;
await streamingCall.WriteCompleteAsync();
await printResponses;
return 0;
}
My problem is that I want to update the content of the Textbox1control but it doesn´t work. It writes perfectly the output into the console with the line Console.WriteLine(alternative.Transcript); but not into my textbox.
If someone could help I would appreciate so much his help.
The problem is that you're using Task.Run, which means your code will be running on a thread-pool thread.
Instead of calling Task.Run(), just move that code into a separate async method:
async Task DisplayResponses(IAsyncEnumerator<StreamingRecognizeResponse> responses)
{
while (await responses.MoveNext(default(CancellationToken)))
{
foreach (var result in responses.Current.Results)
{
foreach (var alternative in result.Alternatives)
{
Textbox1.Text = alternative.Transcript;
}
}
}
}
Then call that method directly (without Task.Run) from code that's already on the UI thread (e.g. an event handler).
The async machinery will make sure that after the await expression, you're back on the UI thread (the same synchronization context). So the assignment to the Text property will occur on the UI thread, and all should be well.
For example:
// This would be registered as the event handler for a button
void HandleButtonClick(object sender, EventArgs e)
{
var stream = client.StreamingRecognize();
// Send the initial config request
await stream.WriteAsync(...);
// Presumably you want to send audio data...
StartSendingAudioData(stream);
await DisplayResponses(stream.ResponseStream);
}
Tasks run on seperate threads, so you must Invoke an action that will be performed on the control's thread
Textbox1.Invoke(new Action(() =>
{
Textbox1.Text= "";
}));
Edit: For WPF, I believe the equivalent is
Textbox1.Dispatcher.Invoke(new Action(() =>
{
Textbox1.Text= "";
}));
have you tried using Dispatcher.InvokeASync()?
await Dispatcher.InvokeAsync(() => {while (await streamingCall.ResponseStream.MoveNext(default(CancellationToken)))
{
foreach (var result in streamingCall.ResponseStream
.Current.Results)
{
foreach (var alternative in result.Alternatives)
{
Textbox1.Text = alternative.Transcript;
}
}
}});
I have a problem with my server uwp side.
I try do unhide some components like this but my app hangs on :
private async void StreamSocketListener_ConnectionReceived(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
{
string request;
using(var streamReader = new StreamReader(args.Socket.InputStream.AsStreamForRead()))
{
request = await streamReader.ReadLineAsync();
}
await this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () => this.txtBlk_Events.Text = request);
if (request.Length > 0)
{
btnSend.Visibility = Visibility.Visible;
}
}
It is possible to do that or not ?
Thanks for your answer
Visibility is a UI property and must be set on the UI thread. In your case it will run on the same thread the ConnectionReceived event handler is run on (thanks to async/await) which is likely not the UI thread. You should instead set the Visibility within the Dispatcher.RunAsync call to make sure it runs on UI thread.
private async void StreamSocketListener_ConnectionReceived(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
{
string request;
using(var streamReader = new StreamReader(args.Socket.InputStream.AsStreamForRead()))
{
request = await streamReader.ReadLineAsync();
}
var setVisibility = request.Length > 0;
await this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
this.txtBlk_Events.Text = request;
if ( setVisibility )
{
btnSend.Visibility = Visibility.Visible;
}
});
}
I'm initializing and starting five threads in my Testing Class:
[Test]
public void ReportGeneratorFiveThreadTest()
{
var threads = new List<ReportGeneratorThread>();
var logger = new Log4NetLogger(typeof(ReportGeneratorThreadTest));
for (var i = 0; i < 5; i++)
{
var estimatedReportSize = EstimatedReportSize.Normal;
var thread = new ReportGeneratorThread(logger, new ReportGenerator(20), estimatedReportSize, new ManualResetEvent(false));
thread.Name = string.Format("ReportGeneratorThread{0}", i);
threads.Add(thread);
}
threads.ForEach(t => t.Start());
}
And I'm starting all threads by calling following method in ReportGeneratorThread class:
public void Start()
{
this.running = true;
this.t = new Thread(this.GenerateReport());
this.t.SetApartmentState(ApartmentState.STA);
this.t.Start();
}
Which calls a GenerateReport() method in order to perform an operation:
public void GenerateReport()
{
var didwork = false;
try
{
didwork = this.reportGenerator.GenerateReport(this.estimatedReportSize);
}
catch (Exception e)
{
this.log.LogError(ReportGenerator.CorrelationIdForPickingReport, string.Format(CultureInfo.InvariantCulture, "System"), string.Format(CultureInfo.InvariantCulture, "Error during report generation."), 0, e);
this.doneEvent.Reset();
Debug.WriteLine("Thread is aborted !!!");
}
finally
{
if (!didwork)
{
Thread.Sleep(Settings.Default.ReportGenerationInterval);
}
}
}
My purpose is to inform my main thread once a thread among all five threads gets aborted (an exception is thrown in GenerateReport() method) and restart it in my main thread afterwards. I have tried using ManualResetEvent for that purpose, but it seems like it is not the proper class to use for this purpose. Any approaches ?.
First post here, sorry for starting with asking questions.
In my Windows Phone 7 app I have a working livetile that is beeing triggered by a background agent. But how can I modify the code so the httpwebrequest timeouts after 10 seconds?
Thanks in advance.
protected override void OnInvoke(ScheduledTask task)
{
//TODO: Add code to perform your task in background
var request = (HttpWebRequest)WebRequest.Create(
new Uri("site.com"));
request.BeginGetResponse(r =>
{
var httpRequest = (HttpWebRequest)r.AsyncState;
var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r);
using (var reader = new StreamReader(httpResponse.GetResponseStream()))
{
var response = reader.ReadToEnd();
Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
{
string strResult = response;
/// If application uses both PeriodicTask and ResourceIntensiveTask
if (task is PeriodicTask)
{
// Execute periodic task actions here.
ShellTile TileToFind = ShellTile.ActiveTiles.FirstOrDefault(x => x.NavigationUri.ToString().Contains("TileID=2"));
if (TileToFind != null)
{
StandardTileData NewTileData = new StandardTileData
{
BackgroundImage = new Uri("Pin-to-start.png", UriKind.Relative),
Title = strResult,
Count = null
};
TileToFind.Update(NewTileData);
}
}
else
{
// Execute resource-intensive task actions here.
}
NotifyComplete();
}));
}
}, request);
}
Here is copy/paste from code that i use in one of my apps. It will abort the connection after 60 seconds.
private static void DoWebRequest(string uri)
{
string id = "my_request";
Timer t = null;
int timeout = 60; // in seconds
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
request.Accept = "*/*";
request.AllowAutoRedirect = true;
// disable caching.
request.Headers["Cache-Control"] = "no-cache";
request.Headers["Pragma"] = "no-cache";
t = new Timer(
state =>
{
if (string.Compare(state.ToString(), id, StringComparison.InvariantCultureIgnoreCase) == 0)
{
logger.Write("Timeout reached for connection [{0}], aborting download.", id);
request.Abort();
t.Dispose();
}
},
id,
timeout * 1000,
0);
request.BeginGetResponse(
r =>
{
try
{
if (t != null)
{
t.Dispose();
}
// your code for processing the results
}
catch
{
// error handling.
}
},
request);
}
catch
{
}
}
But how can I modify the code so the httpwebrequest timeouts after 10 seconds?
You mean so it'll call NotifyComplete() regardless of timeouts?-) The catch is that after 15 seconds the task terminates, and gets disabled until it's re-launched by the user (inside your app).
I would recommend using TPL for Silverlight and utilizing the ability to use Tasks for setting a Timeout.
Something like:
protected override void OnInvoke(ScheduledTask task)
{
var fetchTask = FetchData(TimeSpan.FromSeconds(10));
fetchTask.ContinueWith(x =>
{
Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
{
string strResult = x.Result; // mind you, x.Result will be "null" when a timeout occours.
...
NotifyComplete();
}));
});
}
private Task<string> FetchData(TimeSpan timeout)
{
var tcs = new TaskCompletionSource<string>();
var request = (HttpWebRequest)WebRequest.Create(new Uri("site.com"));
Timer timer = null;
timer = new Timer(sender =>
{
tcs.TrySetResult(null);
timer.Dispose();
}, null, (int)timeout.TotalMilliseconds, Timeout.Infinite);
request.BeginGetResponse(r =>
{
var httpRequest = (HttpWebRequest)r.AsyncState;
var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r);
using (var reader = new StreamReader(httpResponse.GetResponseStream()))
{
var response = reader.ReadToEnd();
tcs.TrySetResult(response);
}
});
return tcs.Task;
}