DBHelper类（做个记录）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace Bn6.DBUtility
{
    /// <summary>
    /// 数据操作类
    /// </summary>
    public class DBHelper
    {
        IDbConnection con = null;
        IDbDataAdapter adpt = null;
        IDbCommand com = null;
        IDbTransaction tran = null;
        DataSet ds = null;

        public DBHelper()
        {
            SqlFactory.Dbfile = AppDomain.CurrentDomain.BaseDirectory + "dbconfig.xml";
            this.con = SqlFactory.CreateConnection();
            this.adpt = SqlFactory.CreateDataAdapter();
        }

        private static DBHelper _instance;
        /// <summary>
        /// AccessHelper单例
        /// </summary>
        public static DBHelper Instance
        {
            get 
            {
                if (_instance == null)
                    _instance = new DBHelper();
                return _instance;
            }
        }

        /// <summary>
        /// 开启事务
        /// </summary>
        private void BeginTransaction()
        {
            if (this.con.State == ConnectionState.Open)
            {
                this.tran = this.con.BeginTransaction();
                this.com.Transaction = this.tran;
            }
        }

        /// <summary>
        /// 执行查询的方法
        /// </summary>
        /// <param name="sqlText">T-SQL语句</param>
        /// <returns>DataTable</returns>
        public DataTable Select(string sqlText)
        {
            DataTable dt = null;
            try
            {
                this.com = this.con.CreateCommand();
                this.com.CommandTimeout = 60;
                this.com.CommandText = sqlText;
                this.adpt.SelectCommand = this.com;
                this.ds = new DataSet();
                this.adpt.Fill(ds);
                dt = this.ds.Tables[0];
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }

            return dt;
        }

        /// <summary>
        /// 执行查询的方法
        /// </summary>
        /// <param name="sqlText">T-SQL语句</param>
        /// <returns>DataTable</returns>
        public DataSet GetDataSet(string sqlText)
        {
            try 
            {
                this.com = this.con.CreateCommand();
                this.com.CommandTimeout = 60;
                this.com.CommandText = sqlText;
                this.adpt.SelectCommand = this.com;
                this.ds = new DataSet();
                this.adpt.Fill(ds);
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }

            return this.ds;
        }

        /// <summary>
        /// 执行增、删、改的方法
        /// </summary>
        /// <param name="sqlText">T-SQL语句</param>
        /// <returns>结果：等于0执行失败，大于0执行成功</returns>
        public int Modify(string sqlText)
        {
            int result = 0;
            try
            {
                this.com = this.con.CreateCommand();
                this.com.CommandTimeout = 60;
                this.com.CommandText = sqlText;

                this.con.Open();
                this.BeginTransaction();
                result = this.com.ExecuteNonQuery();
                this.tran.Commit();
            }
            catch (Exception ex)
            {
                this.tran.Rollback();
                throw new Exception(ex.Message);
            }
            finally
            {
                this.con.Close();
            }

            return result;
        }

        /// <summary>
        /// 批量插入数据
        /// </summary>
        /// <param name="sqlText">T-SQL语句</param>
        /// <returns>结果：等于0执行失败，大于0执行成功</returns>
        public int BatchInsert(string sqlText)
        {
            int result = 0;
            try
            {
                this.com = this.con.CreateCommand();
                this.com.CommandTimeout = 90;
                string[] sql = sqlText.Split(';');
                this.con.Open();
                this.BeginTransaction();
                for (int i = 0; i < sql.Length; i++)
                {
                    this.com.CommandText = sql[i];
                    this.com.ExecuteNonQuery();
                    result++;
                }
                this.tran.Commit();
            }
            catch (Exception ex)
            {
                this.tran.Rollback();
                throw new Exception(ex.Message);
            }
            finally
            {
                this.con.Close();
            }

            return result;
        }

        /// <summary>
        /// 返回首行首列，通常用于Count、Sum、Max、Min等函数返回的值
        /// </summary>
        /// <param name="sqlText">T-SQL语句</param>
        /// <returns>字符串</returns>
        public string GetCount(string sqlText)
        {
            string value = "";
            try
            {
                this.com = this.con.CreateCommand();
                this.com.CommandTimeout = 60;
                this.com.CommandText = sqlText;
                this.con.Open();
                object objResult = this.com.ExecuteScalar();
                if (objResult != null || Convert.IsDBNull(objResult))
                {
                   value =  objResult.ToString();
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            finally
            {
                this.con.Close();
            }
            return value;
        }

        /// <summary>
        /// 返回用于批量导入数据的SqlBulkCopy实例
        /// </summary>
        /// <returns></returns>
        public SqlBulkCopy GetSqlBulkCopy()
        {
            try
            {
                SqlFactory.Dbfile = AppDomain.CurrentDomain.BaseDirectory + "dbconfig.xml";
                IDbConnection newConn = SqlFactory.CreateConnection();
                SqlBulkCopy sbc=new SqlBulkCopy(newConn.ConnectionString);
                //每批次提交5000行数据
                sbc.BatchSize = 5000;
                //延长超时时间
                sbc.BulkCopyTimeout = 300;
                return sbc;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }       
    }
}