Vista Aero ToolStrip on Non-Client Area

• Download demo - 15.3 KB
• Download source code - 60.7 KB

Introduction

When trying to figure out how to give the Ribbon an orb and the quick access toolbar, I found myself in trouble. I hope this example works for something you may need.

Background

Take a look to some Office app with a ribbon (Word, Excel, PowerPoint). There are some things that you might notice at first sight:

1. The orb is drawn half on the client area, half on the title bar
2. The quick access tools are drawn (and sensed) on the title bar
3. The title of the window is centered between the available space and the start of the caption buttons (minimize, maximize, close)

Using the code

Although it seems like the orb and the tools are drawn on the non-client area, they are not. This trick is done with one of the features of Vista's Desktop Window Manager (DWM).

How? Well, a regular window has a client area and a non-client area:

But, a form with the trick done has no client area at all:

So, why does the form look like it has a client area? A very well known trick: DwmExtendFrameIntoClientArea.

Turns out that when extending the frame into the client area, caption buttons (minimize, maximize, close) are drawn by default. To give life to these caption buttons, the DwmDefWindowProc function is called.

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

    int dwmHandled = Dwm.DwmDefWindowProc(m.HWnd, m.Msg, 
                         m.WParam, m.LParam, out result);

    if (dwmHandled == 1)
    {
        m.Result = result;
        return;
    }

    ... 

Now, we have to provide basic frame features like window moving and resizing. This is solved by handling the WM_NCHITTEST message on the WndProc. The return value for this message can specify which part of the frame the mouse is currently hitting. By a measurement of areas, the code returns the correct result:

• Caption
• North
• South
• East
• West
• NorthWest
• NorthEast
• SouthEast
• SouthWest

Drawing the ToolStrip

To add a ToolStrip to the window, I just placed it as usual:

and modified the render process so the ToolStrip gets no background:

public class NonClientAreaRenderer
        : ToolStripProfessionalRenderer
{

    protected override void OnRenderToolStripBackground(ToolStripRenderEventArgs e)
    {
        if (e.ToolStrip.IsDropDown)
        {
            base.OnRenderToolStripBackground(e);
        }
        else
        {
            //Clear so Aero glass covers the area
            e.Graphics.Clear(Color.Transparent);
        }
    }
    ...

And, there you go. A nice toolbar just on the non-client area, but you know, it's not the non-client area :)

History

• 17 Jan. 09 - Original post.
• 06 Feb. 09 - Focus bug fixed.