/// <include file='doc\ScrollBar.uex' path='docs/doc[@for="ScrollBar.WmReflectScroll"]/*' />
/// <devdoc>
/// </devdoc>
/// <internalonly/>
private void WmReflectScroll(ref Message m)
{
ScrollEventType id = (ScrollEventType)NativeMethods.Util.LOWORD(m.WParam);
// For Rtl systems we need to swap increment and decrement
//
if (RightToLeft == RightToLeft.Yes)
{
switch (id)
{
case ScrollEventType.First:
id = ScrollEventType.Last;
break;
case ScrollEventType.Last:
id = ScrollEventType.First;
break;
case ScrollEventType.SmallDecrement:
id = ScrollEventType.SmallIncrement;
break;
case ScrollEventType.SmallIncrement:
id = ScrollEventType.SmallDecrement;
break;
case ScrollEventType.LargeDecrement:
id = ScrollEventType.LargeIncrement;
break;
case ScrollEventType.LargeIncrement:
id = ScrollEventType.LargeDecrement;
break;
}
}
int newValue = value;
// The ScrollEventArgs constants are defined in terms of the windows
// messages.. this eliminates confusion between the VSCROLL and
// HSCROLL constants, which are identical.
//
switch (id)
{
case ScrollEventType.First:
newValue = minimum;
break;
case ScrollEventType.Last:
newValue = maximum - LargeChange + 1; // si.nMax - si.nPage + 1;
break;
case ScrollEventType.SmallDecrement:
newValue = Math.Max(value - SmallChange, minimum);
break;
case ScrollEventType.SmallIncrement:
newValue = Math.Min(value + SmallChange, maximum - LargeChange + 1); // max - lChange + 1);
break;
case ScrollEventType.LargeDecrement:
newValue = Math.Max(value - LargeChange, minimum);
break;
case ScrollEventType.LargeIncrement:
newValue = Math.Min(value + LargeChange, maximum - LargeChange + 1); // si.nPos + si.nPage,si.nMax - si.nPage + 1);
break;
case ScrollEventType.ThumbPosition:
case ScrollEventType.ThumbTrack:
NativeMethods.SCROLLINFO si = new NativeMethods.SCROLLINFO();
si.fMask = NativeMethods.SIF_TRACKPOS;
SafeNativeMethods.GetScrollInfo(new HandleRef(this, Handle), NativeMethods.SB_CTL, si);
if (RightToLeft == RightToLeft.Yes)
{
newValue = ReflectPosition(si.nTrackPos);
}
else
{
newValue = si.nTrackPos;
}
break;
}
ScrollEventArgs se = new ScrollEventArgs(id, newValue);
OnScroll(se);
Value = se.NewValue;
}
private int AdjustScroll(Message m, int pos, int maxPos, bool horizontal)
{
switch (NativeMethods.Util.LOWORD(m.WParam))
{
case NativeMethods.SB_THUMBPOSITION:
case NativeMethods.SB_THUMBTRACK:
NativeMethods.SCROLLINFO si = new NativeMethods.SCROLLINFO();
si.cbSize = Marshal.SizeOf(typeof(NativeMethods.SCROLLINFO));
si.fMask = NativeMethods.SIF_TRACKPOS;
int direction = horizontal ? NativeMethods.SB_HORZ : NativeMethods.SB_VERT;
if (SafeNativeMethods.GetScrollInfo(new HandleRef(this, m.HWnd), direction, si))
{
pos = si.nTrackPos;
}
else
{
pos = NativeMethods.Util.HIWORD(m.WParam);
}
break;
case NativeMethods.SB_LINEUP:
if (pos > SCROLL_LINE)
{
pos -= SCROLL_LINE;
}
else
{
pos = 0;
}
break;
case NativeMethods.SB_LINEDOWN:
if (pos < maxPos - SCROLL_LINE)
{
pos += SCROLL_LINE;
}
else
{
pos = maxPos;
}
break;
case NativeMethods.SB_PAGEUP:
if (pos > SCROLL_PAGE)
{
pos -= SCROLL_PAGE;
}
else
{
pos = 0;
}
break;
case NativeMethods.SB_PAGEDOWN:
if (pos < maxPos - SCROLL_PAGE)
{
pos += SCROLL_PAGE;
}
else
{
pos = maxPos;
}
break;
}
return(pos);
}