C# ADO.NET操作数据库 SqlHelp.cs类

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ADONET
{
    class SqlHelper
    {
        private static string connStr = ConfigurationManager.ConnectionStrings["dbConnStr"].ConnectionString;

        public static int ExecuteNonQuery(string sql,SqlParameter[] parameters)
        { 
            using(SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using(SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    //foreach (SqlParameter parm in parameters)
                    //{
                    //    cmd.Parameters.Add(parm);
                    //}
                    cmd.Parameters.AddRange(parameters);
                    return cmd.ExecuteNonQuery();
                }
            }
        }

        public static object ExecuteScalar(string sql, SqlParameter[] parameters)
        {
            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    cmd.Parameters.AddRange(parameters);
                    return cmd.ExecuteScalar();
                }
                
            }
        }

        public static DataTable ExecuteDataSet(string sql, SqlParameter[] parameters)
        {
            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    cmd.Parameters.AddRange(parameters);
                    SqlDataAdapter adapter = new SqlDataAdapter();
                    DataSet dataset = new DataSet();
                    adapter.Fill(dataset);
                    return dataset.Tables[0];
                }

            }
            
        }
    }
}