Suppose that you want an "error" (or "warning") dialog-
box that closes automatically,
say after 60 seconds. You want to call that dialog from your code just like
you call Delphi's dialogs,
for example call like this:
TimedDlg.Execute('Warning',
'Unexpected value in edit-box AGE. Please correct.');
Here's a quick and simple solution:
- Add a new form to your project and name the form TimedDlg. Save
the new unit as TimedDlgU.
- Set the form's BorderStyle property to bsDialog.
- Add three components:
- a TTimer; set its property Interval to 60000 (that's
60000 milliseconds); set its
property Enabled to False;
- a TMemo;
- a TBitButton; set its property Kind to bkOK.
- In the PUBLIC section of unit TimedDlgU, declare a procedure with the
name Execute:
unit TimedDlgU;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, Buttons;
type
TTimedDlg = class(TForm)
btnOK: TBitBtn;
private
{ Private declarations }
public
{ Public declarations }
procedure Execute(Title, Contents:
string); // added by you
end;
var
TimedDlg: TTimedDlg;
- In the implementation section of your new unit, add the
following code:
procedure TTimedDlg.Execute(Title, Contents: string);
begin
Caption := Title; // set the caption of the
form
Memo1.Text := Contents; // set the text of the memo
Timer1.Enabled := True; // start the timer
ShowModal;
end;
- Double click on the TTimer component. Delphi will write an
"OnTimer" event handler
in your code.
- Complete this "OnTimer" procedure as follows:
procedure TTimedDlg.Timer1Timer;
begin
Timer1.Enabled := False; // stop the timer
ModalResult := mrOK; // close the form
end;
The procedure Execute shows the form in a "modal" way, that
means: the dialog form appears on top of the other window(s) and your
application doesn't continue
before the dialog form is closed.
When the user clicks the OK button, the dialog form is closed.
But if the user doesn't click the OK button within 60 seconds, this form
is closed "automatically".
Note: don't forget to add the unit TimedDlgU to the uses
directive in each unit
from where you call TimedDlg.Execute, like this:
uses ..., ..., TimedDlgU;
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