DBHelper类

using System;using System.Collections.Generic;using System.Text;using System.Data;using System.Data.SqlClient;namespace NewsMIS.DAL{    public static class DBHelper    {        private static SqlConnection connection;        public static SqlConnection Connection        {            get            {                string connectionString = "server=.;uid=sa;pwd=tcaccp;database=NewsDB";                if (connection == null)                {                    connection = new SqlConnection(connectionString);                    connection.Open();                }                else if (connection.State == System.Data.ConnectionState.Closed)                {                    connection.Open();                }                else if (connection.State == System.Data.ConnectionState.Broken)                {                    connection.Close();                    connection.Open();                }                return connection;            }        }        public static int ExecuteCommand(string safeSql)        {            SqlCommand cmd = new SqlCommand(safeSql, Connection);            int result = cmd.ExecuteNonQuery();            return result;        }        public static int ExecuteCommand(string sql, params SqlParameter[] values)        {            SqlCommand cmd = new SqlCommand(sql, Connection);            cmd.Parameters.AddRange(values);            return cmd.ExecuteNonQuery();        }        public static int GetScalar(string safeSql)        {            SqlCommand cmd = new SqlCommand(safeSql, Connection);            int result = Convert.ToInt32(cmd.ExecuteScalar());            return result;        }        public static int GetScalar(string sql, params SqlParameter[] values)        {            SqlCommand cmd = new SqlCommand(sql, Connection);            cmd.Parameters.AddRange(values);            int result = Convert.ToInt32(cmd.ExecuteScalar());            return result;        }        public static SqlDataReader GetReader(string safeSql)        {            SqlCommand cmd = new SqlCommand(safeSql, Connection);            SqlDataReader reader = cmd.ExecuteReader();            return reader;        }        public static SqlDataReader GetReader(string sql, params SqlParameter[] values)        {            SqlCommand cmd = new SqlCommand(sql, Connection);            cmd.Parameters.AddRange(values);            SqlDataReader reader = cmd.ExecuteReader();            return reader;        }        public static DataTable GetDataSet(string safeSql)        {            DataSet ds = new DataSet();            SqlCommand cmd = new SqlCommand(safeSql, Connection);            SqlDataAdapter da = new SqlDataAdapter(cmd);            da.Fill(ds);            return ds.Tables[0];        }        public static DataTable GetDataSet(string sql, params SqlParameter[] values)        {            DataSet ds = new DataSet();            SqlCommand cmd = new SqlCommand(sql, Connection);            cmd.Parameters.AddRange(values);            SqlDataAdapter da = new SqlDataAdapter(cmd);            da.Fill(ds);            return ds.Tables[0];        }    }