protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case WM_ERASEBKGND:
return;
case (int)WinApi.Messages.WM_NCPAINT:
NCPaint(ref m);
return;
case WM_PAINT:
PAINTSTRUCT paintStruct = new PAINTSTRUCT();
IntPtr screenHdc = BeginPaint(m.HWnd, ref paintStruct);
using (Graphics screenGraphics = Graphics.FromHdc(screenHdc))
{
Rectangle clipRect = new Rectangle(paintStruct.rcPaint.left,
paintStruct.rcPaint.top,
paintStruct.rcPaint.right - paintStruct.rcPaint.left,
paintStruct.rcPaint.bottom - paintStruct.rcPaint.top);
int width = (mdiClient.ClientRectangle.Width > 0 ? mdiClient.ClientRectangle.Width : 0);
int height = (mdiClient.ClientRectangle.Height > 0 ? mdiClient.ClientRectangle.Height : 0);
using (Image i = new Bitmap(width, height))
{
using (Graphics g = Graphics.FromImage(i))
{
IntPtr hdc = g.GetHdc();
Message printClientMessage = Message.Create(m.HWnd, WM_PRINTCLIENT, hdc, IntPtr.Zero);
DefWndProc(ref printClientMessage);
g.ReleaseHdc(hdc);
OnPaint(new PaintEventArgs(g, clipRect));
}
screenGraphics.DrawImage(i, mdiClient.ClientRectangle);
}
}
EndPaint(m.HWnd, ref paintStruct);
return;
case WM_SIZE:
mdiClient.Invalidate();
break;
case WM_NCCALCSIZE:
NCCalcSize(ref m);
return;
}
if (m.Msg == (int)WM_FORM_ACTIVE_CHANGED)
{
OnUpdateMDITabsState(m.WParam);
}
base.WndProc(ref m);
}
protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case NativeWindowCommon.WM_VSCROLL:
case NativeWindowCommon.WM_HSCROLL:
//keep all FitToMDI children at location 0,0 even after scroll
foreach (var item in mdiClient.MdiChildren)
{
TagData tagData = item.Tag as TagData;
if (tagData != null && (tagData.WindowType == WindowType.FitToMdi || tagData.IsMDIClientForm))
{
item.Location = new Point();
}
}
mdiClient.Invalidate();
break;
case NativeWindowCommon.WM_PAINT:
using (Graphics gr = Graphics.FromHwnd(mdiClient.Handle))
{
//Paint the mdiClient its children, background image, border etc.
ControlRenderer.PaintMgPanel(mdiClient, gr);
NativeWindowCommon.ValidateRect(mdiClient.Handle, IntPtr.Zero);
}
return;
default:
break;
}
base.WndProc(ref m);
}
private void MdiForm_SizeChanged(object sender, EventArgs e)
{
if (_background_cache != null)
{
_background_cache.Dispose();
}
_background_cache = null;
if (_mdi_client != null)
{
_mdi_client.Invalidate();
}
}
protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
//Do all painting in WM_PAINT to reduce flicker.
case (int)Win32.Msgs.WM_ERASEBKGND:
return;
case (int)Win32.Msgs.WM_PAINT:
// This code is influenced by Steve McMahon's article:
// "Painting in the MDI Client Area".
// http://vbaccelerator.com/article.asp?id=4306
// Use Win32 to get a Graphics object.
Win32.PAINTSTRUCT paintStruct = new Win32.PAINTSTRUCT();
IntPtr screenHdc = User32.BeginPaint(m.HWnd, ref paintStruct);
using (Graphics screenGraphics = Graphics.FromHdc(screenHdc))
{
// Get the area to be updated.
Rectangle clipRect = paintStruct.rcPaint;
// Double-buffer by painting everything to an image and
// then drawing the image.
int width = (MdiClient.ClientRectangle.Width > 0 ? MdiClient.ClientRectangle.Width : 0);
int height = (MdiClient.ClientRectangle.Height > 0 ? MdiClient.ClientRectangle.Height : 0);
if (width > 0 && height > 0)
{
using (Image i = new Bitmap(width, height))
{
using (Graphics g = Graphics.FromImage(i))
{
// This code comes from J Young's article:
// "Generating missing Paint event for TreeView and ListView".
// http://www.codeproject.com/cs/miscctrl/genmissingpaintevent.asp
// Draw base graphics and raise the base Paint event.
IntPtr hdc = g.GetHdc();
Message printClientMessage = Message.Create(m.HWnd, (int)Win32.Msgs.WM_PRINTCLIENT, hdc, IntPtr.Zero);
DefWndProc(ref printClientMessage);
g.ReleaseHdc(hdc);
// Draw the image here.
if (Image != null)
{
DrawImage(g, clipRect);
}
// Call our OnPaint here to draw graphics over the
// original and raise our Paint event.
OnPaint(new PaintEventArgs(g, clipRect));
}
// Now draw all the graphics at once.
screenGraphics.DrawImage(i, MdiClient.ClientRectangle);
}
}
}
User32.EndPaint(m.HWnd, ref paintStruct);
return;
case (int)Win32.Msgs.WM_SIZE:
// Repaint on every resize.
MdiClient.Invalidate();
break;
case (int)Win32.Msgs.WM_NCCALCSIZE:
// If AutoScroll is set to false, hide the scrollbars when the control
// calculates its non-client area.
if (!AutoScroll)
{
User32.ShowScrollBar(m.HWnd, (int)Win32.ScrollBars.SB_BOTH, 0 /*false*/);
}
break;
}
base.WndProc(ref m);
}
private void MdiClient_Resize(object sender, EventArgs e)
{
mdiClient.Invalidate();
}