Как вставить даные в StringGrid из файла?

procedure TForm1.BitBtn2Click(Sender: TObject);
var
Rows,Cols:Integer;
i,j:Integer;
f:TextFile;
begin
Cols:=StringGrid3.ColCount;
Rows:=StringGrid3.RowCount;
if not SaveDialog1.Execute then Exit;
AssignFile(f,SaveDialog1.FileName);
Rewrite(f);
Write(f,IntToStr(Cols),' ',IntToStr(Rows));
writeln(f);
for i:=1 to Rows-1 do
begin
for j:=1 to Cols-1 do
Write(f,StringGrid3.Cells[j,i], ' ');
Writeln(f);
end;
CloseFile(f);
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
var
Rows,Cols: Integer;
i,j:Integer;
f:TextFile;
s:string;
begin
if not OpenDialog1.Execute then Exit;
AssignFile(f,OpenDialog1.FileName);
Reset(f);
Read(f,s);
Cols:=StrToInt(s);
Read(f,s);
Rows:= StrToInt(s);
for i:=0 to Cols-1 do begin
for j:=0 to Rows-1 do begin
Read(f, s);
StringGrid1.Cells[i,j]:=s;
end;
Readln(f);
end;
CloseFile(f);
end;

var
Rows,Cols: Integer;
i,j:Integer;
f:TextFile;
s:string;
  begin
  if not OpenDialog1.Execute then Exit;
 
  AssignFile(f, OpenDialog1.FileName);
  Reset(f);
  Readln(f, s);
  Cols := StrToInt(s);
  Readln(f, s);
  Rows := StrToInt(s);
  for i := 0 to Cols - 1 do
  begin
   for j := 0 to Rows - 1 do
   begin
     Readln(f, s);
     StringGrid1.Cells[i, j] := s;
   end;
   //Readln(f);
  end;
  CloseFile(f);
end;