mobile number already exists Private bool CheckMobNoExistOrNot (string MobileNo) { bool ReturnVal = false; try { if (objCon.State != ConnectionState.Open) ObjCon.Open(); using (SqlCommand cmd = new SqlCommand("select COUNT(*) from tablename where ContactNo=@MobNo ", ObjCon)) { cmd.Parameters.AddWithValue("@MobNo", MobileNo); object Obj = cmd.ExecuteScalar(); if (Obj != ...