封装SQLHelper

//

//	author:	agile

//	datetime:5/29/2011 8:59:13 AM

//	class:	SQLHelper

//

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data.SqlClient;

using System.Configuration;

using System.Data;



namespace SqlHelper

{

    class SQLHelper

    {

        public static int ExecuteNonQuery(string sql,params SqlParameter[] parameters) 

        {

            string conn = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;

            using (SqlConnection strconn = new SqlConnection(conn)) 

            {

                strconn.Open();

                using (SqlCommand cmd = strconn.CreateCommand()) 

                {

                    cmd.CommandText = sql;

                    foreach (SqlParameter parameter in parameters)

                    {

                        cmd.Parameters.Add(parameter); 

                    }

                    return cmd.ExecuteNonQuery();

                }

            }



        }

        public static object ExecuteScalar(string sql, params SqlParameter[] parameters) 

        {

            string conn = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;

            using (SqlConnection strconn = new SqlConnection(conn))

            {

                strconn.Open();

                using (SqlCommand cmd = strconn.CreateCommand())

                {

                    cmd.CommandText = sql;

                    foreach (SqlParameter parameter in parameters)

                    {

                        cmd.Parameters.Add(parameter);

                    }

                    return cmd.ExecuteScalar();

                }

            }



        }

        public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters)

        {

            string conn = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;

            using (SqlConnection strconn = new SqlConnection(conn))

            {

                strconn.Open();

                using (SqlCommand cmd = strconn.CreateCommand())

                {

                    cmd.CommandText = sql;

                     foreach (SqlParameter parameter in parameters)

                    {

                        cmd.Parameters.Add(parameter);

                    }

                    DataSet dataset = new DataSet();

                    SqlDataAdapter adapter = new SqlDataAdapter(cmd);

                    adapter.Fill(dataset);

                    return dataset.Tables[0];

                      



                 }             

            }

           



        }

    }

}

使用：

  string name = Convert.ToString(SQLHelper.ExecuteScalar("select name from T_persons where id=@id", new SqlParameter("id", 20)));