根据传智写的SqlHelper

  1 using System;
  2 using System.Configuration;
  3 using System.Data;
  4 using System.Data.SqlClient;
  5 
  6 namespace ADO连接数据库
  7 {
  8     public static class SqlHelper
  9     {
 10         //首先是连接字符串
 11         private static readonly string Strcon = ConfigurationManager.ConnectionStrings["mssqlserver"].ConnectionString;
 12 
 13         /// <summary>
 14         /// 增删改返回单条无内容ExcuteNonQuery方法
 15         /// </summary>
 16         /// <param name="sql">Sql执行语句</param>
 17         /// <param name="pms">传入变量</param>
 18         /// <returns></returns>
 19         public static int ExcuteNonQuery(string sql, params SqlParameter[] pms)
 20         {
 21             using (SqlConnection con = new SqlConnection(Strcon))
 22             {
 23                 using (SqlCommand cmd = new SqlCommand(sql, con))
 24                 {
 25                     if (pms != null)
 26                     {
 27                         cmd.Parameters.AddRange(pms);
 28                     }
 29                     con.Open();
 30                     return cmd.ExecuteNonQuery();
 31                 }
 32             }
 33         }
 34 
 35         /// <summary>
 36         /// 查询返回单条数据内容ExcuteScalar方法
 37         /// </summary>
 38         /// <param name="sql">Sql执行语句</param>
 39         /// <param name="pms">传入参数</param>
 40         /// <returns></returns>
 41         public static object ExcuteScalar(string sql, params SqlParameter[] pms)
 42         {
 43             using (SqlConnection con = new SqlConnection(Strcon))
 44             {
 45                 using (SqlCommand cmd = new SqlCommand(sql, con))
 46                 {
 47                     if (pms != null)
 48                     {
 49                         cmd.Parameters.AddRange(pms);
 50                     }
 51                     con.Open();
 52                     return cmd.ExecuteScalar();
 53                 }
 54             }
 55         }
 56         /// <summary>
 57         /// 查询Reader方法
 58         /// </summary>
 59         /// <param name="sql">Sql执行语句</param>
 60         /// <param name="pms">传入参数</param>
 61         /// <returns></returns>
 62         public static SqlDataReader Reader(string sql, params SqlParameter[] pms)
 63         {
 64             SqlConnection con = new SqlConnection(Strcon);
 65             using (SqlCommand cmd = new SqlCommand(sql, con))
 66             {
 67                 if (pms != null)
 68                 {
 69                     cmd.Parameters.AddRange(pms);
 70                 }
 71                 try
 72                 {
 73                     con.Open();
 74                     return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
 75                 }
 76                 catch (Exception)
 77                 {
 78                     con.Close();
 79                     con.Dispose();
 80                     throw;
 81                 }
 82             }
 83         }
 84         /// <summary>
 85         /// DataTable方法
 86         /// </summary>
 87         /// <param name="sql">Sql执行语句</param>
 88         /// <param name="pms">可变Sql参数</param>
 89         /// <returns></returns>
 90         public static DataTable Adapter(string sql, params SqlParameter[] pms)
 91         {
 92             DataTable dt = new DataTable();
 93             using (SqlDataAdapter adapter = new SqlDataAdapter(sql, Strcon))
 94             {
 95                 if (pms != null)
 96                 {
 97                     adapter.SelectCommand.Parameters.AddRange(pms);
 98                 }
 99                 adapter.Fill(dt);
100             }
101             return dt;
102         }
103     }
104 }

PS：需要引用一个配置文件

1 <?xml version="1.0" encoding="utf-8" ?>
2 <configuration>
3   <connectionStrings>
4     <add connectionString="Data Source=DESKTOP-B0QVA84;Catalog=MyfirstOne;Integrated Security=True" name="mssqlserver" />
5   </connectionStrings>
6 </configuration>