Delphi 7 - how to use Inputbox - delphi

Question

I am programming a program where you have to enter a password into a InputBox to gain access to the programs min features . But I have a problem if you click on cancel on the inputbox my program gives a error message . So i wanted to know if any one know how I can get that right because with the Messagedlg I know you use IF . But how can I get it right with a InputBox ?

Answer 1

InputBox() returns a blank string if the dialog is canceled, eg:
var
Pass: String;
Pass := InputBox('Password needed', 'Enter the password:');
if Pass <> '' then
begin
// use Pass as needed...
end;
Alternatively, use InputQuery() instead, which returns a Boolean to indicate whether the dialog was canceled or not, eg:
var
Pass: String;
if InputQuery('Password needed', 'Enter the password:', Pass) then
begin
// use Pass as needed...
end;

Answer 2

Many times it is better to have a custom InputQuery
function InputValor(const aCaption: String; APrompt: string; var aValor:
String): Boolean;
var
vForm : TForm;
vLabel : TLabel;
vBtnOk : TBitBtn;
vValor : TEdit;
vBtnCancel : TBitBtn;
begin
Result := False;
vForm := TForm.Create(Application);
vLabel := TLabel.Create(vForm);
vValor := TEdit.Create(vForm);
vBtnOk := TBitBtn.Create(vForm);
vBtnCancel := TBitBtn.Create(vForm);
with vForm do
begin
Name := 'frmValor';
Position := poScreenCenter;
BorderIcons := [biSystemMenu];
BorderStyle := bsDialog;
Caption := aCaption;
ClientHeight := 150;
ClientWidth := 515;
Color := clBtnFace;
OldCreateOrder := False;
Font.Charset := DEFAULT_CHARSET;
Font.Color := clWindowText;
Font.Height := -11;
Font.Name := 'Tahoma';
Font.Style := [];
OldCreateOrder := False;
PixelsPerInch := 96;
Left := 0;
Top := 0;
end;
with vLabel do
begin
Name := 'vLabel';
Parent := vForm;
AutoSize := False;
Left := 18;
Top := 15;
Width := 484;
Height := 41;
Caption := APrompt;
WordWrap := True;
end;
with vValor do
begin
Name := 'vValorEdit';
Parent := vForm;
Left := 18;
Top := 62;
Width := 484;
Height := 21;
Text := '';
end;
with vBtnOk do
begin
Name := 'vBtnOk';
Parent := vForm;
Caption := 'Aceptar';
Left := 335;
Top := 103;
Width := 75;
Height := 25;
TabOrder := 1;
ModalResult := mrOk;
end;
with vBtnCancel do
begin
Name := 'vBtnCancel';
Parent := vForm;
Caption := 'Cancelar';
Left := 427;
Top := 103;
Width := 75;
Height := 25;
TabOrder := 2;
ModalResult := mrCancel;
end;
vForm.ShowModal;
if (vForm.ModalResult = mrOk) and (vValor.Text <> '') then
begin
Result := True;
aValor := vValor.Text;
end else
begin
Result := False;
aValor := '';
end;
FreeAndNil(vForm);
end;
Use in the same way as the Official:
var
vTest : String;
begin
if (InputValor('Title', 'Label text', vTest) = True) then
ShowMessage(vTest);
end;