Hi together,

I have a "sliding" form on my desktop which can be expanded or
collapsed in a sliding manner. So my problem is, that if the form is
collapsing, I want to refresh or invalidate that region on the desktop.

I already tried it with something like this:

-----> snip

[DllImport("user32.dll", SetLastError = true)]
public static extern bool InvalidateRect(
IntPtr hWnd,
ref Rectangle lpRect,
bool bErase);

[DllImport("user32.dll")]
public extern static IntPtr GetDesktopWindow();

// just a rectangle on the whole screen for testing
Rectangle invalidateRect = new Rectangle(0,0,1280,1024);

InvalidateRect(GetDesktopWindow(), ref invalidateRect, true);


----> snap

So InvalidateRect returns with true, but the desktop isn't refreshed.
It's really confusing and I spent a long time - but I can't it getting
work.

What can I do to refresh a rectangle on the desktop???


Kind regards
Franz

You should not need to invalidate the desktop. The window system should take
care of repainting the desktop automatically. Have you tested on another
system to see if you have a driver problem? Or a conflict with another piece
of software?

Regards,
Frank Hileman

check out VG.net: http://www.vgdotnet.com
Animated vector graphics system
Integrated Visual Studio .NET graphics editor

<fdauo (AT) yahoo (DOT) de> wrote

Ok,

before I make my sliding effect I apply the following functions:

// Stop redrawing:
SendMessage(this.Handle, (int)Win32Api.MessageDef.WM_SETREDRAW,
// 0, IntPtr.Zero);

and after the sliding effect is done I reactivate the painting again.

// Start redrawing:
SendMessage(this.Handle, (int)Win32Api.MessageDef.WM_SETREDRAW,
1, IntPtr.Zero);

this.Refresh();

As I understand the functions - only my sliding form should be affected
(this.Handle).
So I think because of these two SendMessage calls I have to repaint the
desktop by myself - and so I am searching for a way to invalidate the
desktop region?

Kind regards,
Franz

Sorry,

this line:

// Stop redrawing:
SendMessage(this.Handle, (int)Win32Api.MessageDef.WM_SETREDRAW,
// 0, IntPtr.Zero);

should be as follows:

// Stop redrawing:
SendMessage(this.Handle, (int)Win32Api.MessageDef.WM_SETREDRAW,
0, IntPtr.Zero);