Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

   procedure TForm1.Button1Click(Sender: TObject);
   { by P. Below }
   const
     DEFBORDER = 8;
   var
     max, temp, i, n: Integer;
   begin
     with Grid do
     begin
       Canvas.Font := Font;
       for n := Low(Columns) to High(Columns) do
       begin
         max := 0;
         for i := 0 to RowCount - 1 do
         begin
           temp := Canvas.TextWidth(Cells[Columns[n], i]) + DEFBORDER;
           if temp > max then
             max := temp;
         end; { For }
         if max > 0 then
           ColWidths[Columns[n]] := max;
       end; { For }
     end; { With }
   end; {SetGridColumnWidths  }