Doesn't work using thread but works if code is inside win form

Question

I have looked for a solution for my problem, but I couldn't find it yet.

I'm coding a bot which will be connected to an irc server. I want the user to have access to a win forms window where it is possible to input the server, channel, and so on.

This is the window:

enter image description here

I have set the console output to update my textbox with the code in the main program. With this, I get all text coming from the child classes into my text box.

static class Program
{
    private static Form1 Form1;
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {

        using (var consoleWriter = new ConsoleWriter())
        {
            consoleWriter.WriteLineEvent += consoleWriter_WriteLineEvent;

            Console.SetOut(consoleWriter);
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Form1 = new Form1();
            Application.Run(Form1);
        }
    }

    static void consoleWriter_WriteLineEvent(object sender, ConsoleWriterEventArgs msg)
    {
        var message = msg.Value;
        Form1.statusTextBox.AppendText(message + "\r\n");
    }
}

public class ConsoleWriter : TextWriter
{
    public override Encoding Encoding { get { return Encoding.UTF8; } }

    public override void Write(string value)
    {
        if (WriteEvent != null) WriteEvent(this, new ConsoleWriterEventArgs(value));
        base.Write(value);
    }

    public override void WriteLine(string value)
    {
        if (WriteLineEvent != null) WriteLineEvent(this, new ConsoleWriterEventArgs(value));
        base.WriteLine(value);
    }

    public event EventHandler<ConsoleWriterEventArgs> WriteEvent;
    public event EventHandler<ConsoleWriterEventArgs> WriteLineEvent;
}

public class ConsoleWriterEventArgs : EventArgs
{
    public string Value { get; private set; }
    public ConsoleWriterEventArgs(string value)
    {
        Value = value;
    }
}

Now I call this in my Form1, when the button "Connect" is clicked on:

 gbaIrcBot.Connect(server, null, port, nick, channelList);

Inside the gbaIrcBot.Connect(), i have among other things:

    private void ReadStream()
    {
        string inputLine;
        while ((inputLine = _streamReader.ReadLine()) != null)
        {
            var splitInput = inputLine.Split(new[] { ' ' });
            if (splitInput.ElementAt(0) == "PING") { Pong(splitInput.ElementAt(1)); continue;}

            switch (splitInput.ElementAt(1))
            {
                case "001":         foreach (var channel in ChannelList) JoinChannel(channel);  break;
                case "PRIVMSG":     ProcessPrivMsg(splitInput);                                 break;
                case "433":         SetNick("AlternativeBOT");                                  break;
                default: Console.WriteLine(inputLine); break;
            }
        }
    }

This method is responsible for reading all inputs from the irc server. When I get messages from the server, I send it to the console, which updates the textbox in Form1. It MUST be an infinite loop.

All this works well if I dont create a thread to keep my UI not frozen. This is an example:

enter image description here

When I try to create a thread, My Form1 throws an exception saying its a cross-thread message, and I cannot update it from outside.

Any idea to solve it?

if you are using background worker, you should be able to use OnProgressChanged event to update the UI. If you need to change a setting in the running thread, you can cancel the thread and start a new one with the updated settings. — jle, Feb 26 '14 at 17:42

score 0 · Answer 1 · edited May 23 '17 at 12:03

0

WinForms UI updates have to be performed on the UI thread. Try this approach:

How to update the GUI from another thread in C#?

edited May 23 '17 at 12:03

Community

1
1

answered Feb 26 '14 at 17:41

jlew

10,491
1
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score 0 · Answer 2 · answered Feb 26 '14 at 17:43

The update on the form must be done in the window update thread.

You can force the execution in such thread by wrapping your call with BeginInvoke().

Change

Form1.statusTextBox.AppendText(message + "\r\n");

to

Form1.BeginInvoke(() => Form1.statusTextBox.AppendText(message + "\r\n"));

Doesn't work using thread but works if code is inside win form

2 Answers2