Question

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.

Answer 1

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;
}