I solve this problem using this code
if ((dt.Rows[i]["IsSaved"].Equals(DBNull.Value) ? 0 : Convert.ToInt32(dt.Rows[i]["IsSaved"] ?? "0")) != 0 && (dt.Rows[i]["IsApplied"].Equals(DBNull.Value) ? 0 : Convert.ToInt32(dt.Rows[i]["IsApplied"] ?? "0")) != 0)
{
str += " <input style=\"border: none;background-color:gray;\" id=\"unsave" + JobID + "\" type=\"button\" class=\"log_in btn_sm\" value=\"UNSAVE\" onclick=\"ShowCurrentTime(" + JobID + ",'unsave')\"/>" +
" <input style=\"border: none;background-color:gray;\" id=\"applied" + JobID + "\" type=\"button\" class=\"sign_up_cc btn_sm\" value=\"APPLIED\" />";
}