Question

This is the code I’m using:

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
            progressBar1.Value = e.ProgressPercentage;
            progressBar1.Refresh();
            int percent = (int)(((double)(progressBar1.Value - progressBar1.Minimum) /
(double)(progressBar1.Maximum - progressBar1.Minimum)) * 100);
            using (Graphics gr = progressBar1.CreateGraphics())
            {
                gr.DrawString(percent.ToString() + "%",
                    SystemFonts.DefaultFont,
                    Brushes.Black,
                    new PointF(progressBar1.Width / 2 - (gr.MeasureString(percent.ToString() + "%",
                        SystemFonts.DefaultFont).Width / 2.0F),
                    progressBar1.Height / 2 - (gr.MeasureString(percent.ToString() + "%",
                        SystemFonts.DefaultFont).Height / 2.0F)));
            }


            listBox1.Items.Add( "Converting File: " + e.UserState.ToString());
            textBox1.Text = e.ProgressPercentage.ToString();
}

While it’s processing and moving to the right the percentages are some blinkings it’s not smooth enough.

And also when its finishing the process in the end the percentages are gone only the green color is left.

Answer 1

I just tried your code and I see your problem, this is a good question. I researched around and found you need to handle the progress bar’s Paint event and draw on e.Graphics.
Otherwise, your drawing will be overwritten next time the control paints itself.

In general, you should never draw on CreateGraphics(). The best way is to subclass the progressbar.

What you need to do first is create a new class like this

class MyProgressBar : ProgressBar
{
    public MyProgressBar()
    {
        this.SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        Rectangle rect = this.ClientRectangle;
        Graphics g = e.Graphics;

        ProgressBarRenderer.DrawHorizontalBar( g, rect );
        rect.Inflate(-3, -3);
        if ( this.Value > 0 )
        {
            Rectangle clip = new Rectangle( rect.X, rect.Y, ( int )Math.Round( ( ( float )this.Value / this.Maximum ) * rect.Width ), rect.Height );
            ProgressBarRenderer.DrawHorizontalChunks(g, clip);
        }

        // assumes this.Maximum == 100
        string text = this.Value.ToString( ) + '%';

        using ( Font f = new Font( FontFamily.GenericMonospace, 10 ) )
        {
            SizeF strLen = g.MeasureString( text, f );
            Point location = new Point( ( int )( ( rect.Width / 2 ) - ( strLen.Width / 2 ) ), ( int )( ( rect.Height / 2 ) - ( strLen.Height / 2 ) ) );
            g.DrawString( text, f, Brushes.Black, location ); 
        }
    }
}

Then goto the InitializeComponent method like below below and update this.progressBar1 = System.Windows.Forms.ProgressBar();
to this.progressBar1 = new MyProgressBar();

#region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.progressBar1 = new MyProgressBar();

This should now work as you wanted. You code will then be reduced to this

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
            progressBar1.Value = e.ProgressPercentage;

            listBox1.Items.Add( "Converting File: " + e.UserState.ToString());
            textBox1.Text = e.ProgressPercentage.ToString();
}