sqlserver插入数据并返回主键

string sql = string.Format("insert into t_user(login_name,password,user_name,phonenumber,status) VALUES ('{0}','{1}','{2}','{3}',{4}); select @@IDENTITY", model.U_Account, model.U_Password, model.businessname, model.tel, 1);
SqlConnection con = new SqlConnection();
con.ConnectionString = "Data Source =.; database=AAA;User ID=***;Password=***;Integrated Security=false;";
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = sql;
con.Open();
int Id = Convert.ToInt32(cmd.ExecuteScalar());//只会读取第一条数据
con.Close();