procedure TMDIChild.FormMouseWheel(Sender: TObject; Shift: TShiftState;
WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
begin
if WheelDelta < 0 then
ScrollBox1.Perform()
ScrollBox1.Perform(WM_VSCROLL, SB_LINEDOWN, 0)
else
ScrollBox1.Perform(WM_VSCROLL, SB_LINEUP, 0);
end;为什么我运行的时候告诉我Undeclared identifier: 'WM_VSCROLL'?
'WM_VSCROLL'还需要定义吗?如果需要怎么定义呢?
WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
begin
if WheelDelta < 0 then
ScrollBox1.Perform()
ScrollBox1.Perform(WM_VSCROLL, SB_LINEDOWN, 0)
else
ScrollBox1.Perform(WM_VSCROLL, SB_LINEUP, 0);
end;为什么我运行的时候告诉我Undeclared identifier: 'WM_VSCROLL'?
'WM_VSCROLL'还需要定义吗?如果需要怎么定义呢?
uses
messages;
Not enough actual parameters
这又是什么原因?