如何在进度条控件上显示文本并保持原始背景

Question

When overriding OnPaint() and OnPaintBackground() events as follows :

protected override void OnPaint( PaintEventArgs e ) {
    base.OnPaint( e );
    try {
        switch ( TextVisibility  ) {
            case ProgressBarTextVisibility.None:
                return;
            case ProgressBarTextVisibility.CustomText:
                if ( progressText=="" ) { return; }
                break;
            case ProgressBarTextVisibility.Percentage:
                progressText = Value.ToString()+"%";
                break;
        }

        SizeF charSize = e.Graphics.MeasureString( progressText, ProgressFont );
        e.Graphics.DrawString(
            progressText,
            ProgressFont,
            new SolidBrush(ProgressTextColor),
            new PointF(
                Width/2-( charSize.Width/2.0F ),
                Height/2-( charSize.Height/2.0F )
            )
        );

    } catch ( Exception ee ) {

    }
}

protected override void OnPaintBackground( PaintEventArgs pevent ) {
    base.OnPaintBackground( pevent );
}

The result is this (progressbar is at 50%) [ pointing out that the background is not drawn at all. ] :

I get the same result as depicted above if i create a new Label control and set it's background to Color.Transparent and set dock to Full .

There are plenty of examples on how to add text AND draw a custom progress bar style, however I wish to keep the original progress bar visual in-tact without re-inventing the wheel. The progress portion works fine and I am happy with the native style and do not wish to redraw my own custom adaptation of it. I only wish to overlay text on top.

I have considered a Timer control / etc, however I also wish to keep this using as few resources as possible.

Here are some of the resources I have already been through :

• How do I put text on ProgressBar?
• Add The Percent Into A Progress Bar (Updated)
• How do put text on ProgressBar?
• ... and many more similar to above

I am using c# and the control is a custom control that extends the .NET native ProgressBar control.

UPDATE

I will use this section to post ongoing research as I find more relevant data that is different.

• Using Visual Styles with Custom and Owner-Drawn Controls - this is not in .NET
• OwnerDraw ComboBox is not “styled” anymore - tried this, but progressbar doen't support DrawMode
• Enabling Visual Styles - this is more for how to enable styling of controls for applications compiled that don't already do this natively (for example, Visual Basic 6, Visual C++ 6, etc)
• VisualStyleElement.ProgressBar.Bar Class - seems to be warm. no full example on implementation so will play the guessing game to try this.
• TabControl OwnerDraw and keep the windows theme... - not a whole lot of information here, but this is how I kind of guessed at the VisualStyleElement.ProgressBar.Bar class as possibly existing.

Answer 1

Override OnLoad and call SetStyle(ControlStyles.AllPaintingInWmPaint, false) and SetStyle(ControlStyles.UserPaint, true). That will separate background and control detail drawing.