PdfPCell cell1 = null;
 cell1 = new PdfPCell(new Phrase(string.Format("{0}", c1), fn));
 cell1.Border = Rectangle.RIGHT_BORDER | Rectangle.LEFT_BORDER;

PdfPTable ItemTable = new PdfPTable(7);
    ItemTable.TableEvent = new LineaBottom();

public class LineaBottom : IPdfPTableEvent
{


    #region IPdfPTableEvent Members

    void IPdfPTableEvent.TableLayout(PdfPTable table, float[][] widths, float[] heights, int headerRows, int rowStart, PdfContentByte[] canvases)
    {
        int columns;
        Rectangle rect;
        int footer = widths.Length - table.FooterRows;
        int header = table.HeaderRows - table.FooterRows + 1;
        int ultima = footer - 1;
        if (ultima != -1)
        {
            columns = widths[ultima].Length - 1;
            rect = new Rectangle(widths[ultima][0], heights[ultima], widths[footer - 1][columns], heights[ultima + 1]);
            rect.BorderColor = BaseColor.BLACK;
            rect.BorderWidth = 1;
            rect.Border = Rectangle.TOP_BORDER;
            canvases[PdfPTable.BASECANVAS].Rectangle(rect);
        }
    }

    #endregion
}