本文共 3132 字，大约阅读时间需要 10 分钟。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;using System.Data;namespace DOT_DAL{       public class DBhelper    {           SqlConnection con = null;        SqlCommand cmd = null;        SqlDataAdapter sdater = null;        DataTable table = null;        string constring = "server=.;database=MyBack;uid=sa;pwd=123456";        //其中server后面跟的是你服务器的名字，database后面跟的是你要连接数据库的名字，SSPI不需要修改        /// 
        /// 执行查询语句        /// 
        /// sql        /// 参数        /// 
   
    返回值
           public DataTable select(string  sql,List
   
       parmaeter=null)        {               try            {                   using (con = new SqlConnection(constring))                {                       con.Open();                    using (cmd = new SqlCommand(sql, con))                    {                           if (parmaeter != null)                        {                               cmd.Parameters.AddRange(parmaeter.ToArray());                        }                            sdater = new SqlDataAdapter(sql, con);                            table = new DataTable();                            sdater.Fill(table);                                                   }                }            }            catch (Exception)            {                   throw;            }            return table;                       }        /// 
    
        /// 查询单行单列        /// 
        /// 
    sql        /// 
    参数        /// 
    
     返回值
            public object ExecuteScalar(string sql, List
    
      parmaeter = null)        {               object obj=null;            try            {                   using (con = new SqlConnection(constring))                {                       con.Open();                    using (cmd = new SqlCommand(sql, con))                    {                           if (parmaeter != null)                        {                               cmd.Parameters.AddRange(parmaeter.ToArray());                        }                        obj = cmd.ExecuteScalar();                    }                }            }            catch (Exception)            {                   throw;            }            return obj;        }        /// 
     
        /// 查询添加，修改，删除        /// 
        /// 
     sql        /// 
     参数        /// 
     
      返回值
             public int ExecuteNonQuery(string sql, List
     
       parmaeter = null)        {               int row = 0;            try            {                   using (con = new SqlConnection(constring))                {                       con.Open();                    using (cmd = new SqlCommand(sql, con))                    {                           if (parmaeter != null)                        {                               cmd.Parameters.AddRange(parmaeter.ToArray());                        }                        row = cmd.ExecuteNonQuery();                    }                }            }            catch (Exception)            {                   throw;            }            return row;        }            }}