Посмотрел в исходниках... Нашел в StdCtrls.pas следующее:
| Код |
procedure TCustomComboBox.KeyPress(var Key: Char);
function HasSelectedText(var StartPos, EndPos: DWORD): Boolean;
begin
SendMessage(Handle, CB_GETEDITSEL, Integer(@StartPos), Integer(@EndPos));
Result := EndPos > StartPos;
end;
procedure DeleteSelectedText;
var
StartPos, EndPos: DWORD;
OldText: String;
begin
OldText := Text;
SendMessage(Handle, CB_GETEDITSEL, Integer(@StartPos), Integer(@EndPos));
Delete(OldText, StartPos + 1, EndPos - StartPos);
SendMessage(Handle, CB_SETCURSEL, -1, 0);
Text := OldText;
SendMessage(Handle, CB_SETEDITSEL, 0, MakeLParam(StartPos, StartPos));
end;
var
StartPos: DWORD;
EndPos: DWORD;
OldText: String;
SaveText: String;
Msg : TMSG;
LastByte: Integer;
begin
inherited KeyPress(Key);
if not AutoComplete then exit;
if Style in [csDropDown, csSimple] then
FFilter := Text
else
begin
if GetTickCount - FLastTime >= 500 then
FFilter := '';
FLastTime := GetTickCount;
end;
case Ord(Key) of
VK_ESCAPE: exit;
VK_TAB:
if FAutoDropDown and DroppedDown then
DroppedDown := False;
VK_BACK:
begin
if HasSelectedText(StartPos, EndPos) then
DeleteSelectedText
else
if (Style in [csDropDown, csSimple]) and (Length(Text) > 0) then
begin
SaveText := Text;
LastByte := StartPos;
while ByteType(SaveText, LastByte) = mbTrailByte do Dec(LastByte);
OldText := Copy(SaveText, 1, LastByte - 1);
SendMessage(Handle, CB_SETCURSEL, -1, 0);
Text := OldText + Copy(SaveText, EndPos + 1, MaxInt);
SendMessage(Handle, CB_SETEDITSEL, 0, MakeLParam(LastByte - 1, LastByte - 1));
FFilter := Text;
end
else
begin
while ByteType(FFilter, Length(FFilter)) = mbTrailByte do
Delete(FFilter, Length(FFilter), 1);
Delete(FFilter, Length(FFilter), 1);
end;
Key := #0;
Change;
end;
else // case
if FAutoDropDown and not DroppedDown then
DroppedDown := True;
if HasSelectedText(StartPos, EndPos) then
SaveText := Copy(FFilter, 1, StartPos) + Key
else
SaveText := FFilter + Key;
if Key in LeadBytes then
begin
if PeekMessage(Msg, Handle, 0, 0, PM_NOREMOVE) and (Msg.Message = WM_CHAR) then
begin
if SelectItem(SaveText + Char(Msg.wParam)) then
begin
PeekMessage(Msg, Handle, 0, 0, PM_REMOVE);
Key := #0
end;
end;
end
else
if SelectItem(SaveText) then
Key := #0
end; // case
end;
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Из этого мне не совсем понятно, откуда берется звук! Странно... Кто объяснит непонимающему? |