multithreading exception

[Acidburn]

Hey guys, I've an issue when it comes to multithreading

i seem to get this error after updating a variable...

Cross-thread operation not valid: Control 'progressBar1' accessed from a thread other than the thread it was created on.

Basically I'm trying to use a progress bar indicator to show the applications status. Any ideas of what i'm doing wrong here?

Thanks...

[dickersonka]

here's something i made from another post with the same question

you need to use invokerequired to be able to do this

private delegate void UpdatePbDelegate();
        private void UpdatePb()
        {
            if (this.pbStatus.InvokeRequired)
            {
                UpdatePbDelegate updateCount = new UpdatePbDelegate(this.UpdatePb);
                this.pbStatus.Invoke(updateCount);
            }
            else
            {
                if(this.pbStatus.Value == 100)
		{
			this.pbStatus.Value = 1;
		}
                this.pbStatus.PerformStep();
                this.pbStatus.Refresh();
            }
        }


private void DownloadData()
{
//your code in here that downloads your values
}

private void StartingThread()
{
 Thread t= new Thread(new ThreadStart(DownloadData));
            t.Start();

            while (t.IsAlive)
            {
                UpdatePb();
                System.Threading.Thread.Sleep(50);
            }
}

[Acidburn]

namespace pb
{
    using System;
    using System.Drawing;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Threading;


    /// <summary>
    ///    Summary description for Win32Form2.
    /// </summary>
    public partial class Win32Form2 : System.Windows.Forms.Form
    {

        /// <summary>
        ///    Required by the Win Forms designer
        /// </summary>
        private System.ComponentModel.Container components;
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.ProgressBar progressBar1;

        public Win32Form2()
        {
            // Required for Win Form Designer support
            InitializeComponent();
        }

        /// <summary>
        ///    The main entry point for the application.
        /// </summary>
        public static void Main(string[] args)
        {
            Application.Run(new Win32Form2());
        }

        /// <summary>
        ///    Required method for Designer support - do not modify
        ///    the contents of this method with an editor
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.label1 = new System.Windows.Forms.Label();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.button1 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();

            //@design this.TrayHeight = 0;
            //@design this.TrayLargeIcon = false;
            //@design this.TrayAutoArrange = true;
            label1.Location = new System.Drawing.Point(32, 40);
            label1.Text = "Progress Value";
            label1.Size = new System.Drawing.Size(88, 24);
            label1.TabIndex = 2;

            progressBar1.Maximum = 100;
            progressBar1.Location = new System.Drawing.Point(8, 312);
            progressBar1.Minimum = 0;
            progressBar1.TabIndex = 0;
            progressBar1.Value = 0;

            //We have calculated the excat size which will result in only 20 boxes to be drawn

            progressBar1.Size = new System.Drawing.Size(520, 40);
            progressBar1.Step = 1;

            button1.Location = new System.Drawing.Point(152, 168);
            button1.Size = new System.Drawing.Size(144, 48);
            button1.TabIndex = 1;
            button1.Text = "button1";
            button1.Click += new System.EventHandler(button1_Click);

            textBox1.Location = new System.Drawing.Point(136, 40);
            textBox1.Text = "0";
            textBox1.TabIndex = 3;
            textBox1.Size = new System.Drawing.Size(184, 20);
            this.Text = "Win32Form2";
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(616, 393);
            this.Click += new System.EventHandler(Win32Form2_Click);

            this.Controls.Add(textBox1);
            this.Controls.Add(label1);
            this.Controls.Add(button1);
            this.Controls.Add(progressBar1);
            Thread t = new Thread(new ThreadStart(testing));
            t.Start();
            
        }

        protected void button1_Click(object sender, System.EventArgs e)
        {

            //this checking is automatically done as stated in the Ref Documentation 
            //but it does not work , BUGssssss 
            //so we have to do it shhhhh .... 
            if (progressBar1.Value == progressBar1.Maximum)
            {
                progressBar1.Value = progressBar1.Minimum;
            }
            progressBar1.PerformStep();
            textBox1.Text = progressBar1.Value.ToString(); // Displays the values of progressbar in textbox

        }

        protected void testing()
        {
            while (progressBar1.Value < 100)
            {
                if (progressBar1.Value == progressBar1.Maximum)
                {
                    progressBar1.Value = progressBar1.Minimum;
                }
                progressBar1.PerformStep();
                textBox1.Text = progressBar1.Value.ToString(); // Displays the values of progressbar in textbox
                System.Threading.Thread.Sleep(50);
            }

        }
        protected void Win32Form2_Click(object sender, System.EventArgs e)
        {
        }
    }

Where does the update count get implemented? I don't get that...

[dickersonka]

in your method for testing you are updating the pb, anywhere you are updating it just call

UpdatePb();