multithreading exception
 

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

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

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...

Re: multithreading exception
 

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);

            }

}

Re: multithreading exception
 

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...

Re: multithreading exception
 

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

UpdatePb();