public virtual IntPtr WindowProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch ((WM)msg)
{
case WM.ACTIVATE:
{
// Initialize offset on window first activation
// Note: this only applies for non-layered style window
if (!_window.AllowsTransparency &&
_window.WindowStyle != WindowStyle.None &&
_offset == null)
{
var offset = GetEdgeOffset();
_offset = offset.Value;
EdgeOffsetChanged(this, new EdgeOffsetChangedEventArgs(offset));
}
break;
}
case WM.SYSCOMMAND:
{
// To obtain the correct result when testing the value of wParam,
// an application must combine the value 0xFFF0 with the wParam
// value by using the bitwise AND operator.
SC command = (SC)(wParam.ToInt32() & 0xFFF0);
_sizing = command == SC.SIZE;
_moving = command == SC.MOVE;
break;
}
case WM.SIZING:
{
_sizingEdge = (WMSZ)wParam.ToInt32();
break;
}
case WM.EXITSIZEMOVE:
{
_sizingEdge = WMSZ.NONE;
break;
}
case WM.WINDOWPOSCHANGING:
{
WINDOWPOS windowPos = (WINDOWPOS)Marshal.PtrToStructure(lParam, typeof(WINDOWPOS));
if (Helpers.WindowChanged(windowPos))
{
switch (ActualState)
{
case WindowState.Minimized:
break;
case WindowState.Maximized:
Unsnap();
break;
default:
// Proceed to snap detection if the current system settings
// allow snapping or if window is currently snapped
if (CanSnap() || _snapped)
{
// Get the list of monitors that intersect with the window area
List <Monitor> monitors = SafeNativeMethods.GetDisplayMonitors(new RECT
{
left = windowPos.x,
top = windowPos.y,
right = windowPos.x + windowPos.cx,
bottom = windowPos.y + windowPos.cy
});
Rect location = new Rect(
Dpi.ToLogicalX(windowPos.x),
Dpi.ToLogicalY(windowPos.y),
Dpi.ToLogicalX(windowPos.cx),
Dpi.ToLogicalY(windowPos.cy));
SnapResult snapResult = DetectSnap.IsSnapped(ref location, monitors, Offset);
if (snapResult.IsSnapped)
{
Snap();
}
else if (Unsnapping)
{
Unsnap();
}
}
break;
}
}
break;
}
}
return(IntPtr.Zero);
}