unit Unit1;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls;

type
 TForm1 = class(TForm)
   SaveDialog1: TSaveDialog;
   Button1: TButton;
   procedure Button1Click(Sender: TObject);
   procedure SaveDialog1Show(Sender: TObject);
 private
   { Private declarations }
 public
   { Public declarations }
 end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
 SaveDialog1.Filter := 'Text File (*.txt)|*.txt|CSS File (*.css)|*.css';

 //SaveDialog1.FileName := 'temp.txt';
 SaveDialog1.FileName := 'temp.css';

 if ExtractFileExt(SaveDialog1.FileName) = '.txt' then
   SaveDialog1.FilterIndex := 1;

 if ExtractFileExt(SaveDialog1.FileName) = '.css' then
   SaveDialog1.FilterIndex := 2;

 SaveDialog1.Execute;
end;

procedure TForm1.SaveDialog1Show(Sender: TObject);
begin
{
 if ExtractFileExt(SaveDialog1.FileName) = '.txt' then
   SaveDialog1.FilterIndex := 1;

 if ExtractFileExt(SaveDialog1.FileName) = '.css' then
   SaveDialog1.FilterIndex := 2;
}
end;

end.