Mega Code Archive
Textboxinput
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procedure TMakeOrEditBForm.NameBoxKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
{we use 'virtual key codes' below -these are useful for trapping keys}
{like up-arrow, down-arrow, backspace, return, etc BUT if for example}
{you want to validate user input it's better to do that by looking at}
{each character in InputBox.Text in turn AFTER the whole line}
{of input is put in by the user rather than by translating from virtual}
{codes to characters as they are typed in: this is because the}
{mapping of 'virtual' to ASCII characters can get complicated and it's}
{better to let Delphi itself do that since by default text gets put}
{into InputBox.Text when the focus shifts away from the input box...}
var
Redundant: Integer;
purpose : String;
begin
purpose := Copy(MakeOrEditBForm.Caption, 1, 4);
{there IS such a thing as a masked edit box (useful for input validation)}
{but this way we've got total control...}
case Key of
VK_UP, VK_LEFT : NameBox.SetFocus;
VK_DOWN, VK_RIGHT : if purpose = 'Seat' then
begin
MakeOrEditBForm.BookedBox.SetFocus
end
else
begin
MakeOrEditBForm.SeatNoBox.SetFocus
end;
VK_RETURN : NameBoxProcess(Redundant);
VK_BACK : NameBox.Clear;
{without next line the shift character on it's own will be considered}
{non-alphabetic so generating an error message...}
VK_SHIFT : {do nothing};
end;
end;
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