I want to compare grid view column date with system date then enable disable link button?

LinkButton lnk2 = (LinkButton)e.Row.FindControl("lnkSelect");
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                string dtimeString = Convert.ToDateTime(e.Row.Cells[2].Text).ToString("yy/MM/dd");

                DateTime dtime = Convert.ToDateTime(dtimeString);

                DateTime nowtime = Convert.ToDateTime(DateTime.Now.ToString("yy/MM/dd"));
                if (dtime == nowtime)
                {
                    lnk2.Enabled = true;
                    //change the column backcolor 
                  //  e.Row.Cells[0].BackColor = System.Drawing.Color.Yellow;

                    //change the row backcolor
                    //  e.Row.BackColor = System.Drawing.Color.Yellow;
                }
                if (dtime > nowtime)
                {
                    lnk2.Enabled = false;
                    e.Row.Cells[0].BackColor = System.Drawing.Color.Red;

                    // e.Row.BackColor = System.Drawing.Color.Red;
                }
            }