Need help with gridview row index after sort.

protected void GridViewSys_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                e.Row.Attributes["onclick"] = Page.ClientScript.GetPostBackClientHyperlink(GridViewSys, "Select$" + e.Row.RowIndex);
                e.Row.ToolTip = "Click to select this row.";
            }
        }

protected void GridViewSys_SelectedIndexChanged(object sender, EventArgs e)
        {
            foreach (GridViewRow row in GridViewSys.Rows)
            {
                if (row.RowIndex == GridViewSys.SelectedIndex)
                {
                    row.BackColor = ColorTranslator.FromHtml("#007bff");
                    row.ToolTip = String.Empty;
                  
                    String sysName, sysDesc, sysVen, sysReq, sysPO, sysLT, sysSOW, sysSLA, sysComp, sysSQ;
                    sysName = row.Cells[0].Text;
                    sysDesc = row.Cells[1].Text;
                    sysVen = row.Cells[2].Text;
                    sysReq = row.Cells[3].Text;
                    sysPO = row.Cells[4].Text;
                    sysLT = row.Cells[5].Text;
                    sysSOW = row.Cells[6].Text;
                    sysSLA = row.Cells[7].Text;
                    sysComp = row.Cells[8].Text;
                    sysSQ = row.Cells[9].Text;

                    txtSysName.Text = sysName;
                    txtSysDesc.Text = Server.HtmlEncode(sysDesc);
                    txtSysVen.Text = sysVen;
                    txtSysReq.Text = sysReq;
                    txtSysPO.Text = sysPO;
                    txtSysLT.Text = sysLT;
                    lblSow.Text = sysSOW;
                    lblSLA.Text = sysSLA;
                    lblComp.Text = sysComp;
                    lblSQ.Text = sysSQ;
                }
                else
                {
                    row.BackColor = ColorTranslator.FromHtml("#FFFFFF");
                    row.ToolTip = "Click to select this row.";
                }
            }