internal static extern bool EndPaint(IntPtr hWnd, ref PAINTSTRUCT ps);
internal static extern IntPtr BeginPaint(IntPtr hWnd, ref PAINTSTRUCT ps);
internal static extern bool EndPaint(IntPtr hWnd, ref PAINTSTRUCT ps);
protected void OnWM_PAINT(ref Message m)
{
PAINTSTRUCT ps = new PAINTSTRUCT();
// Have to call BeginPaint whenever processing a WM_PAINT message
IntPtr hDC = User32.BeginPaint(m.HWnd, ref ps);
RECT rectRaw = new RECT();
// Grab the screen rectangle of the window
User32.GetWindowRect(this.Handle, ref rectRaw);
// Convert to a client size rectangle
Rectangle rectWin = new Rectangle(0, 0,
rectRaw.right - rectRaw.left,
rectRaw.bottom - rectRaw.top);
// Create a graphics object for drawing
using (Graphics g = Graphics.FromHdc(hDC))
{
// Create bitmap for drawing onto
Bitmap memoryBitmap = new Bitmap(rectWin.Width, rectWin.Height);
using(Graphics h = Graphics.FromImage(memoryBitmap))
{
// Draw the background area
DrawBackground(h, rectWin);
// Draw the actual menu items
DrawAllCommands(h);
}
// Blit bitmap onto the screen
g.DrawImageUnscaled(memoryBitmap, 0, 0);
}
// Don't forget to end the paint operation!
User32.EndPaint(m.HWnd, ref ps);
}
internal static extern IntPtr BeginPaint(IntPtr hWnd, ref PAINTSTRUCT ps);
