protected override void WndProc(ref Message m)
{
if (DesignMode)
{
base.WndProc(ref m);
return;
}
switch ((Window.Msg)m.Msg)
{
case Window.Msg.WM_NCCALCSIZE:
// Check WPARAM
if (m.WParam != IntPtr.Zero)
{
// When TRUE, LPARAM Points to a NCCALCSIZE_PARAMS structure
var nccsp = (WinApi.NCCALCSIZE_PARAMS)Marshal.PtrToStructure(m.LParam, typeof(WinApi.NCCALCSIZE_PARAMS));
ApplyPreferedSize(_preferedSize, nccsp.rectProposed.Size);
AdjustClientArea(ref nccsp.rectProposed);
Marshal.StructureToPtr(nccsp, m.LParam, true);
}
else
{
// When FALSE, LPARAM Points to a RECT structure
var clnRect = (WinApi.RECT)Marshal.PtrToStructure(m.LParam, typeof(WinApi.RECT));
ApplyPreferedSize(_preferedSize, clnRect.Size);
AdjustClientArea(ref clnRect);
Marshal.StructureToPtr(clnRect, m.LParam, true);
}
//Return Zero
m.Result = IntPtr.Zero;
break;
case Window.Msg.WM_NCPAINT:
PaintScrollBars(null);
// we handled everything
m.Result = IntPtr.Zero;
break;
case Window.Msg.WM_NCHITTEST:
// we need to correctly handle this if we want the non client area events (WM_NC*) to fire properly!
var point = PointToClient(new Point(m.LParam.ToInt32()));
if (!ClientRectangle.Contains(point))
{
m.Result = (IntPtr)WinApi.HitTest.HTBORDER;
}
else
{
base.WndProc(ref m);
}
break;
case Window.Msg.WM_MOUSEWHEEL:
if (HasScroll)
{
// delta negative when scrolling up
var delta = (short)(m.WParam.ToInt64() >> 16);
var mouseEvent1 = new MouseEventArgs(MouseButtons.None, 0, 0, 0, delta);
if (HorizontalScroll.IsHovered)
{
HorizontalScroll.HandleScroll(null, mouseEvent1);
}
else
{
VerticalScroll.HandleScroll(null, mouseEvent1);
}
}
else
{
// propagate the event
base.WndProc(ref m);
}
break;
case Window.Msg.WM_MOUSEMOVE:
if (VerticalScroll.IsThumbPressed)
{
VerticalScroll.HandleMouseMove(null, null);
}
if (HorizontalScroll.IsThumbPressed)
{
HorizontalScroll.HandleMouseMove(null, null);
}
base.WndProc(ref m);
break;
case Window.Msg.WM_NCMOUSEMOVE:
// track mouse leaving (otherwise the WM_NCMOUSELEAVE message would not fire)
WinApi.TRACKMOUSEEVENT tme = new WinApi.TRACKMOUSEEVENT();
tme.cbSize = (uint)Marshal.SizeOf(tme);
tme.dwFlags = (uint)(WinApi.TMEFlags.TME_LEAVE | WinApi.TMEFlags.TME_NONCLIENT);
tme.hwndTrack = Handle;
WinApi.TrackMouseEvent(tme);
// PointToClient(new Point(m.LParam.ToInt32()));
VerticalScroll.HandleMouseMove(null, null);
HorizontalScroll.HandleMouseMove(null, null);
base.WndProc(ref m);
break;
case Window.Msg.WM_NCLBUTTONDOWN:
VerticalScroll.HandleMouseDown(null, null);
HorizontalScroll.HandleMouseDown(null, null);
Focus();
// here we forward to base button down because it has a internal focus mecanism that we want to exploit
// if we don't do that, the mouse MOVE events are not fired outside the bounds of this control!
m.Msg = (int)Window.Msg.WM_LBUTTONDOWN;
base.WndProc(ref m);
break;
case Window.Msg.WM_NCLBUTTONUP:
case Window.Msg.WM_LBUTTONUP:
VerticalScroll.HandleMouseUp(null, null);
HorizontalScroll.HandleMouseUp(null, null);
// here we forward this message to base WM_LBUTTONUP to release the internal focus on this control
m.Msg = (int)Window.Msg.WM_LBUTTONUP;
base.WndProc(ref m);
break;
case Window.Msg.WM_NCMOUSELEAVE:
VerticalScroll.HandleMouseLeave(null, null);
HorizontalScroll.HandleMouseLeave(null, null);
base.WndProc(ref m);
break;
default:
base.WndProc(ref m);
break;
}
}
protected virtual void MouseLDownClientArea(MouseEventArgs mouseEventArgs)
{
Focus();
VerticalScroll.HandleMouseDown(null, null);
HorizontalScroll.HandleMouseDown(null, null);
}