Code:

procedure TForm1.Button1Click(Sender: TObject);
var
   rootDir:string;
procedure bros(const root:string);
var
   i,j,dirIterate:word;
   subdirs:TstringList;
     a,b:string;
begin
   subdirs:=Tstringlist.Create;
   Directory.Directory:=root;
   Directory.OpenCurrent;
a:=floattostr(j);
   if FileListBox.items.count>0 then
      for j:=0 to FileListBox.items.count-1 do
         begin
         grid.cells[0,grid.RowCount-1]:=fileListBox.Items[j];
         grid.cells[1,grid.RowCount-1]:=root;

         grid.cells[2,grid.RowCount-1]:=NazivFajla(a);
         grid.RowCount:=grid.RowCount+1;
         end;
  if not(Directory.ItemIndex=Directory.Items.Count-1) then
      begin
      for i:=Directory.ItemIndex+1 to Directory.Items.count-1 do
         begin
         if Directory.itemindex=0 then
             subdirs.add(Directory.Directory+Directory.Items[i]) 
           else
             subdirs.add(Directory.Directory+'\'+Directory.Items[i]);
         end;

      for dirIterate:=0 to subdirs.Count-1 do
         bros(subdirs[dirIterate]);
      end;
   subdirs.Free;
end;
begin
FileListBox.Mask:='*.'+Edit.text;
grid.RowCount:=2;
grid.Cells[0,1]:='';
grid.Cells[1,1]:='';
grid.Cells[0,0]:='Naziv fajla';
grid.Cells[1,0]:='Lokacija';
screen.Cursor:=-11;
bros(DirectoryListBox.Directory);
if grid.RowCount > 2 then
   grid.RowCount:=grid.RowCount-1;
if grid.cells[0,1]<>'' then
   Brojfajlova.Caption:='Ukupan broj pronadjenih fajlova: '+inttostr(grid.rowcount-1)
else
   Brojfajlova.Caption:='Ukupan broj pronadjenih fajlova: 0';
screen.Cursor:=0;
end;