C#: Overriding OnPaint on ProgressBar not working?

Question

Was thinking it should be pretty easy to create a ProgressBar that drew some text upon itself. However, I am not quite sure what is happening here...

I added the following two overrides:

    protected override void OnPaintBackground(PaintEventArgs pevent)
    {
        base.OnPaintBackground(pevent);
        var flags = TextFormatFlags.VerticalCenter | TextFormatFlags.HorizontalCenter | TextFormatFlags.SingleLine | TextFormatFlags.WordEllipsis;
        TextRenderer.DrawText(pevent.Graphics, "Hello", Font, Bounds, Color.Black, flags);
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        var flags = TextFormatFlags.VerticalCenter | TextFormatFlags.HorizontalCenter | TextFormatFlags.SingleLine | TextFormatFlags.WordEllipsis;
        TextRenderer.DrawText(e.Graphics, "Hello", Font, Bounds, Color.Black, flags);
    }

However, I get no text, and the methods doesn't even seem to be called. What is going on here?

---

Update: Thanks to the two answers so far, I have gotten it to actually call the OnPaint by using SetStyle(ControlStyles.UserPaint, true), and I have gotten it to draw the text in the right place by sending in new Rectangle(0, 0, Width, Height) instead of Bounds.

I do get text now, but the ProgressBar is gone... and the point was kind of to have the text on top of the ProgressBar. Any idea how I can solve this?

Answer 1

Your problem is that you're passing in Bounds as your Rectangle parameter. Bounds contains the Height and Width of your control, which is what you want, but it also contains the Top and Left properties of your control, relative to the parent form, so your "Hello" is being offset on the control by however much your control is offset on its parent form.

Replace Bounds with new Rectangle(0, 0, this.Width, this.Height) and you should see your "Hello".

Answer 2

I needed to do this myself and I thought that I would post a simplified example of my solution since I could not find any examples. It is actually pretty simple if you use the ProgressBarRenderer class:

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 ); 
        }
    }
}

Answer 3

You could override WndProc and catch the WmPaint message.

The example below paints the Text property of the progressbar in its center.

public class StatusProgressBar : ProgressBar
{
    const int WmPaint = 15;

    protected override void WndProc(ref Message m)
    {
        base.WndProc(ref m);

        switch (m.Msg)
        {
            case WmPaint:
                using (var graphics = Graphics.FromHwnd(Handle))
                {
                    var textSize = graphics.MeasureString(Text, Font);

                    using(var textBrush = new SolidBrush(ForeColor))
                        graphics.DrawString(Text, Font, textBrush, (Width / 2) - (textSize.Width / 2), (Height / 2) - (textSize.Height / 2));
                }
                break;
        }
    }
}

Answer 4

Here's another solution along with other people's suggestions. I subclassed the progressbar control to make this work. I mixed and matched codes from various places for this. The paint event could be cleaner, but that's for you to do ;)

   public class LabeledProgressBar: ProgressBar
   {
      private string labelText;

      public string LabelText
      {
         get { return labelText; }
         set { labelText = value; }
      }

      public LabeledProgressBar() : base()
      { 
         this.SetStyle(ControlStyles.UserPaint, true);
         this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);

         this.Paint += OnLabelPaint;
      }

      public void OnLabelPaint(object sender, PaintEventArgs e)
      {
         using(Graphics gr = this.CreateGraphics())
        {
         string str = LabelText + string.Format(": {0}%", this.Value);
         LinearGradientBrush brBG = new LinearGradientBrush(e.ClipRectangle, 
             Color.GreenYellow, Color.Green, LinearGradientMode.Horizontal);
         e.Graphics.FillRectangle(brBG, e.ClipRectangle.X, e.ClipRectangle.Y, 
             e.ClipRectangle.Width * this.Value / this.Maximum, e.ClipRectangle.Height);
         e.Graphics.DrawString(str, SystemFonts.DefaultFont,Brushes.Black,  
            new PointF(this.Width / 2 - (gr.MeasureString(str, SystemFonts.DefaultFont).Width / 2.0F),
            this.Height / 2 - (gr.MeasureString(str, SystemFonts.DefaultFont).Height / 2.0F)));
         }
       }
    }