how do I feed UI from backgrowndworker thread

I am using following code to update the progress bar <pre lang="c#"> private void btnSearch_Click(object sender, EventArgs e)
        {


            worker.DoWork += worker_DoWork;
            worker.WorkerReportsProgress = true;
            worker.ProgressChanged += worker_ProgressChanged;
            worker.RunWorkerAsync();

        }

        void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            updateUI();
        }


        void worker_DoWork(object sender, DoWorkEventArgs e)
        {

           myfunction();
            Thread.Sleep(100);
            worker.ReportProgress(paths.currentProgress);


        }


        public void updateUI(){
            pBar.Minimum = 0;
            pBar.Maximum = 100;
            pBar.Step = paths.currentProgress; // a value I get from myfunction()
            pBar.PerformStep();
        }</pre>  it do not update the UI(progressbar).

then I tried it this way

<pre lang="c#">private void btnSearch_Click(object sender, EventArgs e)
        {


            worker.DoWork += worker_DoWork;
            worker.RunWorkerAsync();

        }


        void worker_DoWork(object sender, DoWorkEventArgs e)
        {

           myfunction();
            Thread.Sleep(100);
           updateUI();



        }


        public void updateUI(){
            pBar.Minimum = 0;
            pBar.Maximum = 100;
            pBar.Step = paths.currentProgress; // a value I get from myfunction()
            pBar.PerformStep();
        }</pre>

this time it gives me the error
<pre>An exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll but was not handled in user code

Additional information: Cross-thread operation not valid: Control 'pBar' accessed from a thread other than the thread it was created on.</pre>

please help me how do I feed the UI from the function I have called in back ground worker.