OnEnter事件:
var
nHandle: HRGN;
begin
with Combobox1 do
begin
nHandle := CreateRectRgn(0, 0, width, height);
SetWindowRgn(Handle, nHandle, True);
end;
end;
在OnExit事件:
var
nHandle: HRGN;
begin
with Combobox1 do
begin
nHandle := CreateRectRgn(0, 0, width-20, height);
SetWindowRgn(Handle, nHandle, True);
end;
end