1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Data.SqlClient; 6 using System.Configuration; 7 using System.Data; 8  9 namespace adonet10 {11     class SqlHelper12     {13         private static string connStr = ConfigurationManager.ConnectionStrings["dbConnStr"].ConnectionString;14 15         public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)16         {17             using (SqlConnection conn = new SqlConnection(connStr))18             {19                 conn.Open();20                 using (SqlCommand cmd = conn.CreateCommand())21                 {22                     cmd.CommandText = sql;23                     cmd.Parameters.AddRange(parameters);24                     return cmd.ExecuteNonQuery();25                 }26             }27         }28 29         public static object ExecuteScalar(string sql, params SqlParameter[] parameters)30         {31             using (SqlConnection conn = new SqlConnection(connStr))32             {33                 conn.Open();34                 using (SqlCommand cmd = conn.CreateCommand())35                 {36                     cmd.CommandText = sql;37                     cmd.Parameters.AddRange(parameters);38                     return cmd.ExecuteScalar();39                 }40             }41         }42 43         public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters)44         {45             using (SqlConnection conn = new SqlConnection(connStr))46             {47                 conn.Open();48                 using (SqlCommand cmd = conn.CreateCommand())49                 {50                     cmd.CommandText = sql;51                     cmd.Parameters.AddRange(parameters);52 53                     SqlDataAdapter adapter = new SqlDataAdapter(cmd);54                     DataSet dataset=new DataSet();55                     adapter.Fill(dataset);56                     return dataset.Tables[0];57                 }58             }59         }60     }61 }