C#

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

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms; // remove after testing used to show message boxes
using System.Threading;

namespace WindowsFormsApplication1
{



    public partial class thread
    {
        //Properties
        private thread trd;
        private ProgressBar _threadProgressBar;

        public ProgressBar ThreadProgressBar
        {
            set { _threadProgressBar = value; }
            get { return _threadProgressBar; }
        }
        public void startthread()
        {
            
            
            Thread trd = new Thread(new ThreadStart(this.ThreadTask));
            trd.IsBackground = true;
            trd.Start();
        }



        private void ThreadTask()
        {

            int stp;
            int newval;
            Random rnd = new Random();

            while (true)
            {
                stp = ThreadProgressBar.Step * rnd.Next(-1, 2);
                newval = ThreadProgressBar.Value + stp;

                if (newval > ThreadProgressBar.Maximum)
                    newval = ThreadProgressBar.Maximum;
                else if (newval < ThreadProgressBar.Minimum)
                    newval = ThreadProgressBar.Minimum;

                ThreadProgressBar.Value = newval;

                Thread.Sleep(100);
            }
        }
    }
}

public void callthread()
        {
            thread mythread = new thread();
            mythread.ThreadProgressBar = progressBar1;
            mythread.startthread();
        }

private void txtCrap1_TextChanged(object sender, EventArgs e) 
{ 
    Settings.Crap1 = txtCrap1.Text; 
} 

private void SetUpControlBindings() 
{ 
    AddBinding(txtCrap1, Settings.Crap1); 
    AddBinding(txtCrap2, Settings.Crap2); 
} 
private void AddBinding(object control, object value) 
{ 
    //Add entry to some kind of dictionary 
} 
private void UpdateValue(object sender, EventArgs e) 
{ 
    if (sender is TextBox) 
    { 
    //Search it in dictionary and change appropriate value 
    } 
}