C# Access 数据访问类 OleHelper

C# Access 数据访问类 OleHelper

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.OleDb;
using System.Data;
using System.Configuration;
namespace Dal
...{
    public sealed class OleHelper
    ...{
        private OleHelper()
        ...{ }

        public static OleDbConnection Conn
        ...{
            get 
            ...{
                return new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + AppDomain.CurrentDomain.BaseDirectory + ConfigurationSettings.AppSettings["DataName"]);
            }
        }

        public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText)
        ...{
            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, commandType, commandText);

            OleDbDataAdapter da = new OleDbDataAdapter(cmd);

            DataSet ds = new DataSet();

            da.Fill(ds);

            cmd.Parameters.Clear();
            connection.Close();
            return ds;
        }

        public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText, OleDbParameter[] parameters)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, commandType, commandText, parameters);

            DataSet retval = cmd.ExecuteDataset();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, commandType, commandText);

            int retval = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText, OleDbParameter[] parameters)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, commandType, commandText, parameters);

            int retval = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }


        public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, commandType, commandText);

            object retval = cmd.ExecuteScalar();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText, OleDbParameter[] parameters)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, commandType, commandText, parameters);

            object retval = cmd.ExecuteScalar();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, commandType, commandText);

            OleDbDataReader retval = cmd.ExecuteReader();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText,OleDbParameter[] parameters)
        ...{

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, commandType, commandText, parameters);

            OleDbDataReader retval = cmd.ExecuteReader();

            cmd.Parameters.Clear();
            connection.Close();
            return retval;

        }

        private static void PrepareCommand(OleDbCommand command, OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText)
        ...{
            if (connection.State != ConnectionState.Open)
            ...{
                connection.Open();
            }

            command.Connection = connection;

            command.CommandText = commandText;

            if (transaction != null)
            ...{
                command.Transaction = transaction;
            }

            command.CommandType = commandType;

            return;
        }

        private static void PrepareCommand(OleDbCommand command, OleDbConnection connection, CommandType commandType, string commandText,OleDbParameter[] parameters)
        ...{
            if (connection.State != ConnectionState.Open)
            ...{
                connection.Open();
            }

            command.Connection = connection;

            command.CommandText = commandText;

            command.Parameters = parameters;

            command.CommandType = commandType;

            return;
        }
    }
}