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TFindDialog

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TFindDialog is a component that aids in searching information. It can be found on the Dialogs tab of the Component Palette.

It is important to know that the dialog itself does not perform a search; it just provides a user interface for all the search parameters. To activate a FindDialog, call its Execute() function. Create an OnFind method in which the search itself is performed.

Usage

The following examples illustrate usage of TFindDialog for search a specific phrase within the text stored in a memo (TMemo).

pascal
procedure TForm1.Button1Click(Sender: TObject);
begin
  FindDialog1.Execute();
end;

procedure TForm1.FindDialog1Find(Sender: TObject);
var
  k: integer;
begin
  with Sender as TFindDialog do begin
    k := Pos(FindText, Memo1.Lines.Text);
    if k > 0 then begin
      Memo1.SelStart := k - 1;
      Memo1.SelLength := Length(FindText);
      Memo1.SetFocus; // Memo1 must be activated, otherwise the selection effect will not be displayed
    end else
      Beep();
  end;
end;

If you want to repeat the operation several times with the same search text you must remember the last found position and continue searching from here - the function PosEx() in unit StrUtils is perfect for this purpose:

pascal
uses
  StrUtils;

type
  TForm1 = class(TForm)
  private
    FFoundPos: Integer;
    ...

procedure TForm1.Button1Click(Sender: TObject);
begin
  with FindDialog1 do 
  begin
    if frEntireScope in Options then    // Search begins at file start
      FFoundPos := 0
    else
      FFoundPos := Memo1.SelStart;      // Serach begins at current cursor position
    Execute;
  end;
end; 

procedure TForm1.FindDialog1Find(Sender: TObject);
begin
  with Sender as TFindDialog do 
  begin
    FFoundPos := PosEx(FindText, Memo1.Lines.Text, FFoundPos+1);
    if FFoundPos > 0 then 
    begin
      Memo1.SelStart := FFoundPos - 1;
      Memo1.SelLength := Length(FindText);
      Memo1.SetFocus; // Memo1 must be activated, otherwise the selection effect will not be displayed
    end else
      Beep();
  end;
end;

See also


From the Free Pascal wiki, page "TFindDialog", as it stood on 2020-05-01 after a change by TyphonFinger, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.

Revision 2, last changed by WikiArchive .

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