DBHelper类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
namespace ConsoleApp5
{
    internal class DBHelper
    {
        private static string conStr = ConfigurationManager.ConnectionStrings["conStr"].ConnectionString;
        /// <summary>
        /// 增删改
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="param">是否带参数</param>
        /// <param name="isProc">是否是存储过程</param>
        public static void Update(string sql, List<SqlParameter> param, bool isProc)
        {
            using (SqlConnection con = new SqlConnection(conStr))
            {
                con.Open();
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    //判断是否有参数
                    if (param != null)
                    {
                        //批量添加
                        cmd.Parameters.AddRange(param.ToArray());
                    }
                    //判断是否是存储过程
                    if (isProc)
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                    }
                    cmd.ExecuteNonQuery();
                }
            }
        }

        /// <summary>
        /// 查询
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="param">是否带参数</param>
        /// <param name="isProc">是否是存储过程</param>
        public static DataTable Query(string sql, List<SqlParameter> param, bool isProc)
        {
            DataTable dt = new DataTable();
            using (SqlConnection con = new SqlConnection(conStr))
            {
                con.Open();
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    //判断是否有参数
                    if (param != null)
                    {
                        //批量添加
                        cmd.Parameters.AddRange(param.ToArray());
                    }
                    //判断是否是存储过程
                    if (isProc)
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                    }
                    using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                    {
                        da.Fill(dt);
                    }
                }
            }
            return dt;
        }

        public static object Scalar(string sql, List<SqlParameter> param, bool isProc)
        {
            object obj = null;
            using (SqlConnection con = new SqlConnection(conStr))
            {
                con.Open();
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    //判断是否有参数
                    if (param != null)
                    {
                        //批量添加
                        cmd.Parameters.AddRange(param.ToArray());
                    }
                    //判断是否是存储过程
                    if (isProc)
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                    }
                    obj = cmd.ExecuteScalar();
                }
            }
            return obj;
        }
    }
}