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).
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:
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
