Rendering controls on glass: Solution found, needs double-buffering/perfecting

Question

I (finally!) found a way of rendering Windows.Forms controls on glass that doesn\'t seem to have any major drawback nor any big implementation time. It\'s inspired by this artic

Answer 1

I had a problem with flickering before (lots of controls on the form, user controls). Tried almost everything. This is what worked for me:

Have you tried putting this in your form class?

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.ExStyle |= 0x02000000; // WS_EX_COMPOSITED
            cp.ExStyle |= 0x00080000; // WS_EX_LAYERED
            return cp;
        }
    }

And in your constructor you have to enable double buffering, otherwise it won't work:

this.DoubleBuffered = true;
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);

It only works when aero is enabled, if not it can make flickering even worse.

and you can also add this

  protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;

                cp.ExStyle |= 0x02000000; // WS_EX_COMPOSITED
            return cp;
        }
    } 

to your UserControls class.

Answer 2

Here is a version with much less flickering, still not perfect though.

public class GlassControlRenderer : NativeWindow
{
    private Control Control;
    private Bitmap Bitmap;
    private Graphics ControlGraphics;

    private object Lock = new object();

    protected override void WndProc(ref Message m)
    {
        switch (m.Msg)
        {
            case 0x14: // WM_ERASEBKGND
                this.CustomPaint();
                break;

            case 0x0F: // WM_PAINT
            case 0x85: // WM_NCPAINT

            case 0x100: // WM_KEYDOWN
            case 0x101: // WM_KEYUP
            case 0x102: // WM_CHAR

            case 0x200: // WM_MOUSEMOVE
            case 0x2A1: // WM_MOUSEHOVER
            case 0x201: // WM_LBUTTONDOWN
            case 0x202: // WM_LBUTTONUP
            case 0x285: // WM_IME_SELECT

            case 0x300: // WM_CUT
            case 0x301: // WM_COPY
            case 0x302: // WM_PASTE
            case 0x303: // WM_CLEAR
            case 0x304: // WM_UNDO
                base.WndProc(ref m);
                this.CustomPaint();
                break;

            default:
                base.WndProc(ref m);
                break;
        }
    }

    private Point Offset { get; set; }

    public GlassControlRenderer(Control control, int xOffset, int yOffset)
    {
        this.Offset = new Point(xOffset, yOffset);
        this.Control = control;
        this.Bitmap = new Bitmap(this.Control.Width, this.Control.Height);
        this.ControlGraphics = Graphics.FromHwnd(this.Control.Handle);
        this.AssignHandle(this.Control.Handle);
    }

    public void CustomPaint()
    {
        this.Control.DrawToBitmap(this.Bitmap, new Rectangle(0, 0, this.Control.Width, this.Control.Height));
        this.ControlGraphics.DrawImageUnscaled(this.Bitmap, this.Offset); // -1, -1 for content controls (e.g. TextBox, ListBox)
    }
}