I'm a beginner in SignalR. how can I define method in client, and call it from server. here is my code :
in Server :
public class ChatHub : Hub
{
public void ServerMethod()
{
Clients.All.ClientMethod();
}
}
in Client :
HubConnection connection;
IHubProxy proxy;
public MainWindow()
{
InitializeComponent();
connection = new HubConnection("LocalHostDomain");
proxy = connection.CreateHubProxy("ChatHub");
}
private void Call_Click(object sender, RoutedEventArgs e)
{
proxy.Invoke("ServerMethod");
}
private void Start_Click(object sender, RoutedEventArgs e)
{
proxy.On("ClientMethod", () =>
{
tb1.Text = "Hello";
});
connection.Start().Wait();
}
but tb1.Text won't change!! it's very simple, but I don't know how to do it!
The calling thread cannot access this object because a different thread owns it.
SignalR processes the incomming messages in another thread than the UI thread. Changes to the UI must always be performed on the UI thread. Therefore, you need to synchronize access. For example:
private void Start_Click(object sender, RoutedEventArgs e)
{
proxy.On("ClientMethod", () => UpdateLabel());
connection.Start().Wait();
}
private void UpdateLabel()
{
if (InvokeRequired)
{
BeginInvoke(new Action(UpdateLabel));
return;
}
tb1.Text = "Hello";
}
this is how you can do it
private void Start_Click(object sender, RoutedEventArgs e)
{
proxy.On("ClientMethod", () =>
{
change_text("Hello");
});
}
private void change_text(string text)
{
if (tb1.InvokeRequired)
{
tb1.Invoke(new MethodInvoker(delegate { tb1.Text = text; }));
}
else
{
tb1.Text = text;
}
}
you can change the text without having to put it a method. I am just giving you and idea how to do it.
Related
Currently I am using WebSocket-Sharp. I am able to connect to the server through my application and I am able to send a Client.Send(Move.HeadNod); to the server on button click. However even though I declared
private WebSocket client;
const string host="ws://localhost:80";
public Form1()
{
InitializeComponent();
client=new WebSocket(host);
client.connect();
Client.OnMessage+=client_OnMessage
}
where:
client_OnMessage(object sender,MessageEventArgs e)
{
textbox1.text=convert.tostring(e);
client.send(move.headleft);
}
I am still unable to get a response from the server and continue sending command afterwards.
Edit
void Client_OnMessage(object sender,MessageEventArgs e)
{
if(e.IsText)
{
edata=e.data;
return;
}
else if(e.IsBinary)
{
Textbox1.Text=Convert.Tostring(e.RawData);
return;
}
}
This is the complete code that works on my machine. Put a break-point in both event handlers to see what happens. Maybe your web socket server throws an exception and you just don't know it:
public partial class Form1 : Form
{
private readonly WebSocket _client;
public Form1()
{
InitializeComponent();
_client = new WebSocket("ws://echo.websocket.org");
_client.OnMessage += Ws_OnMessage;
_client.OnError += Ws_OnError;
_client.Connect();
}
private void Ws_OnError(object sender, ErrorEventArgs e)
{
}
private void Ws_OnMessage(object sender, MessageEventArgs e)
{
if (e.IsText)
{
Invoke(new MethodInvoker(delegate () {
textBox1.Text = e.Data;
}));
}
else if (e.IsBinary)
{
Invoke(new MethodInvoker(delegate () {
textBox1.Text = Convert.ToString(e.RawData);
}));
}
}
private void button1_Click(object sender, System.EventArgs e)
{
_client.Send("Hi");
}
}
On .NET Windows form, I have Background worker component that works fine. I have 5 forms, that has basically same Background worker on it with same code.
Can I extract this code to other class and somehow use it, considering this is an event? This is code I have on form. It takes 20 lines of code, and it would be nice if this can be refactored. Note: as you can see, I have already put it to other class BackgroundWorkerHelper, but can I also somehow refactor this events on Background worker, so that it is in other class as well, this way code is less and reused.
private void RunBackgroundWorker(string infoLabelText, int imageIndex)
{
BackgroundWorkerHelper.Run(backgroundWorker, progressBar, infoLabelText, imageIndex);
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorkerHelper.DoWork(backgroundWorker);
}
private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
BackgroundWorkerHelper.ProgressChanged(sender, e, progressBar);
}
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
BackgroundWorkerHelper.RunWorkerCompleted(sender, e, progressBar);
}
Note: for now I would like to avoid using user control. I know I could do it, but then you have code that handles placing user control and so on. I am still not very good in it.
Here is solution, thanks to rory who gave me idea how to do it. First, I made this class:
public class BackgroundWorkerHelper
{
private static string _infoLabelText = string.Empty;
public BackgroundWorker _BackgroundWorker;
private BarEditItem _marqueeInfo;//this is marquee progress bar
public BackgroundWorkerHelper(BarEditItem marqueeInfo)
{
_marqueeInfo = marqueeInfo;
_BackgroundWorker = new BackgroundWorker();
_BackgroundWorker.WorkerReportsProgress = true;
_BackgroundWorker.WorkerSupportsCancellation = true;
_BackgroundWorker.DoWork += backgroundWorker_DoWork;
_BackgroundWorker.ProgressChanged += backgroundWorker_ProgressChanged;
_BackgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;
}
public void Run(string labelText, int imageIndex)
{
_marqueeInfo.Caption = labelText;
_marqueeInfo.ImageIndex = imageIndex;
if (!_BackgroundWorker.IsBusy)
_BackgroundWorker.RunWorkerAsync();
else
_marqueeInfo.Caption = "Busy processing saving data, please wait...";
}
public void DoWork()
{
for (int i = 0; i <= 5; i++)
{
_BackgroundWorker.ReportProgress(i); // call backgroundWorker_ProgressChanged event and pass i (which is e argument e.ProgressPercentage) to update UI controls
Thread.Sleep(250);
}
}
public void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
_marqueeInfo.Visibility = BarItemVisibility.Always;
}
public void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
_marqueeInfo.Visibility = BarItemVisibility.Never;
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
DoWork();
}
private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
ProgressChanged(sender, e);
}
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
RunWorkerCompleted(sender, e);
}
then in FORM, in class level above constructor place
private readonly BackgroundWorkerHelper _backgroundWorkerHelper;
then in Form Constructor instantiate class
_backgroundWorkerHelper = new BackgroundWorkerHelper(marqueeInfo);
and then I just call it in my form
_backgroundWorkerHelper.Run("Saving", 14);
private void butt_Click(object sender, EventArgs e)
{
try
{
richTextBox1.Text = RunPreUp("script");
}
catch(exception p) { }
}
My problem is RunPreUP("script") take more than 3 minutes so i want to synchronize the write and read for richTextBox1 from RunPreUp("script");
there is async/await but it's for farmework4.5 and I work on VS2010 framework.3.5.
beast regards
Look into BackgroundWorker class, or ThreadPool class. Either one will let you run lengthy operation, upon completion of which you can update .Text property with the result. Remember that you'll need to do richTextBox1.Invoke to set the property.
Use a separate thread?
I have tested this and it works.
public partial class Form1 : Form
{
private Thread _thread = null;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
ParameterizedThreadStart pts = new ParameterizedThreadStart(RunPreUp);
_thread = new Thread(pts);
_thread.Start("script");
}
private void RunPreUp(object param)
{
string parameter = param as string;
// do work.
string result = "here is a result";
richTextBox1.Invoke((MethodInvoker)delegate
{
richTextBox1.Text = result;
});
Thread.CurrentThread.Abort();
}
}
hey i am new to c# plz help.
i am writing a program that sorts data in a file and it is a time consuming process so i thought that i should run it in a separate thread and since it has alot of step so i made a new class for it. the problem is that i want to show the progress in the main GUI and i know for that i have to use Invoke function but the problem is that the form control variables are not accessible it this class. what should i do ??????
sample code:
public class Sorter
{
private string _path;
public Sorter(string path)
{
_path = path;
}
public void StartSort()
{
try
{
processFiles(_path, "h4x0r"); // Just kidding
}
catch (Exception e)
{
MessageBox.Show("Error: " + e.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
private void processFiles(string Dir, string[] key)
{
/* sorting program */
}
and it is used as
public partial class Form1 : Form
{
Sorter sort;
public Form1()
{
InitializeComponent();
}
private void browseBtn_Click(object sender, EventArgs e)
{
if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
textBox1.Text = folderBrowserDialog1.SelectedPath;
}
private void startBtn_Click(object sender, EventArgs e)
{
if (startBtn.Text == "Start Sorting")
{
Thread worker = new Thread(new ThreadStart(delegate() {
sort = new Sorter(textBox1.Text);
sort.StartSort(); }));
worker.start();
}
else
MessageBox.Show("Cancel");//TODO: add cancelling code here
}
}
plz help..
Add an Event to your class that is doing the multi-threaded work, that triggers when the progress changes. Have your form subscribe to this event and update the progress bar.
Note ProgressEventArgs is a little class that inherits EventArgs and has an Integer for the progress.
// delegate to update progress
public delegate void ProgressChangedEventHandler(Object sender, ProgressEventArgs e);
// Event added to your worker class.
public event ProgressChangedEventHandler ProgressUpdateEvent
// Method to raise the event
public void UpdateProgress(object sender, ProgressEventArgs e)
{
ProgressChangedEventHandler handler;
lock (progressUpdateEventLock)
{
handler = progressUpdateEvent;
}
if (handler != null)
handler(sender, e);
}
I would recommend you read up on the BackgroundWorker class. It is exactly for the problem you are trying to solve and makes things a lot easier than doing manual threading yourself.
Brief Example
public Form1()
{
InitializeComponent();
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.WorkerSupportsCancellation = true;
backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker_ProgressChanged);
}
void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
private void btnStart_Click(object sender, EventArgs e)
{
if (!backgroundWorker.IsBusy)
backgroundWorker.RunWorkerAsync();
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
for (int i = 1; i < 101; ++i)
{
if (backgroundWorker.CancellationPending)
{
e.Cancel = true;
break;
}
else
{
//Sort Logic is in here.
Thread.Sleep(250);
backgroundWorker.ReportProgress(i);
}
}
}
private void btnCancel_Click(object sender, EventArgs e)
{
if (backgroundWorker.IsBusy && backgroundWorker.WorkerSupportsCancellation)
backgroundWorker.CancelAsync();
}
You could do something like this:
public delegate void StatusReporter(double progressPercentage);
public class MainClass
{
public void MainMethod()
{
Worker worker = new Worker(ReportProgress);
ThreadStart start = worker.DoWork;
Thread workThread = new Thread(start);
workThread.Start();
}
private void ReportProgress(double progressPercentage)
{
//Report here!!!
}
}
public class Worker
{
private readonly StatusReporter _reportProgress;
public Worker(StatusReporter reportProgress)
{
_reportProgress = reportProgress;
}
public void DoWork()
{
for (int i = 0; i < 100; i++ )
{
// WORK, WORK, WORK
_reportProgress(i);
}
}
}
There are a few option available to solve this sort of issue. In any case, you will have to fiddle with Invoke to get the UI to update.
You could...
...add an event that fires on your new class which your UI can listen to, and Invoke as applicable - you'd still need to pass the data to your worker class (by constructor, properties, method call, etc)
...keep the method as a method on your form, and pas that to start your new thread from (after all, a new thread doesn't have to be starting in a different class)
...change the access modifiers on your controls to be (say) internal such that any class within the same assembly can Invoke changes to the controls, or read from them.
...make your worker class a child of the form it needs to access - it can then see the privates of its parent, as long as it is passed a reference to the instance.
using System;
using System.Windows.Forms;
using agsXMPP;
using System.Text;
namespace iTalk2
{
public partial class Main : Form
{
agsXMPP.XmppClientConnection objXmpp;
public Main()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
Console.WriteLine("Logging in. Please wait...");
Console.ReadLine();
objXmpp = new agsXMPP.XmppClientConnection();
agsXMPP.Jid jid = null;
jid = new agsXMPP.Jid("username" + "#gmail.com");
objXmpp.Password = "password";
objXmpp.Username = jid.User;
objXmpp.Server = jid.Server;
objXmpp.AutoResolveConnectServer = true;
try
{
objXmpp.OnMessage += messageReceived;
objXmpp.OnAuthError += loginFailed;
objXmpp.OnLogin += loggedIn;
objXmpp.Open();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
Console.ReadLine();
}
}
private void messageReceived(object sender, agsXMPP.protocol.client.Message msg)
{
string[] chatMessage = null;
chatMessage = msg.From.ToString().Split('/');
agsXMPP.Jid jid = null;
jid = new agsXMPP.Jid(chatMessage[0]);
agsXMPP.protocol.client.Message autoReply = null;
autoReply = new agsXMPP.protocol.client.Message(jid, agsXMPP.protocol.client.MessageType.chat, "This is a test");
objXmpp.Send(autoReply);
}
private void loginFailed(object o, agsXMPP.Xml.Dom.Element el)
{
Console.WriteLine("Login failed. Please check your details.");
}
private void loggedIn(object o)
{
Console.WriteLine("Logged in and Active.");
lblStatus.Text = "Online";
}
private void txtUsername_TextChanged(object sender, EventArgs e)
{
}
private void label1_Click(object sender, EventArgs e)
{
}
private void label2_Click(object sender, EventArgs e)
{
}
private void txtPassword_TextChanged(object sender, EventArgs e)
{
}
private void btnlogin_Click(object sender, EventArgs e)
{
}
}
}
This code is not working. the function 'loggedIn(object o)' is not working. it says the lblStatus (which is a label) is on another thread. the error window says "Cross-thread operation not valid: Control 'lblStatus' accessed from a thread other than the thread it was created on." thanks in advance.
You need to invoke a call on the UI thread. If you add code as follows at the top of the loggedIn method it should work:-
if(InvokeRequired)
{
Invoke(new Action<object>(loggedIn), o);
return;
}
WinForms is designed such that controls must only be manipulated on the UI-thread, the thread that runs the message-loop that manages the control.
Try this instead:
private void loggedIn(object o)
{
Console.WriteLine("Logged in and Active.");
Action act = () => lblStatus.Text = "Online";
Invoke(act);
}
If your application is such that this method can be called on the UI thread or a separate worker thread, you'd be better off testing forInvokeRequired(simply: am I on the control's UI thread?) and dealing with the result appropriately. For example,
private void loggedIn(object o)
{
if(InvokeRequired)
Invoke(new Action<object>(loggedIn), o);
else
{
Console.WriteLine("Logged in and Active.");
lblStatus.Text = "Online";
}
}
Note that Invokewill block until the UI-update is completed. If you want something more fire-and-forget, use BeginInvokeinstead.
When you start an application it is running from a single thread. This is the main thread, sometimes called the UI thread (since the UI will usually be rendered at startup and as a consequence it will be on that main thread.
Now, when you listen to events, your methods/delegates will get called from new threads. This is a consequence of the event based design. Normally this is not a problem unless you are trying to share data between two threads. This is exactly what happens with your UI elements. In this case your UI elements were created by your first thread but other threads are trying to update its value.
Given your design, you should check for IsInvokeRequired on the control and if so, use Invoke to set the new value. This will marshal your call from the new thread into the main thread that your UI is running on and will allow you to safely change the control.