AccessHelper

using System;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.Collections;
using System.Text.RegularExpressions;
using Help.Common;

namespace DAL
{
    public abstract class AccessHelper
    {
        public static readonly string ConnectionString = ConfigurationManager.AppSettings["Help"];

        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

        public static int ExecuteNonQuery(CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            return ExecuteNonQuery(ConnectionString, cmdType, cmdText, commandParameters);
        }

        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            using (OleDbConnection conn = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, conn, cmdType, cmdText, commandParameters);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }

        public static int ExecuteNonQuery(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }

        public static OleDbDataReader ExecuteReader(CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            return ExecuteReader(ConnectionString, cmdType, cmdText, commandParameters);
        }

        public static OleDbDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            OleDbConnection conn = new OleDbConnection(connectionString);
            try
            {
                PrepareCommand(cmd, conn, cmdType, cmdText, commandParameters);
                OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }
        }

        public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);
            OleDbDataReader rdr = cmd.ExecuteReader();
            cmd.Parameters.Clear();
            return rdr;
        }

        public static object ExecuteScalar(CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            return ExecuteScalar(ConnectionString, cmdType, cmdText, commandParameters);
        }

        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();

            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }

        public static object ExecuteScalar(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }

        public static DataTable ExecuteTable(CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            return ExecuteTable(ConnectionString, cmdType, cmdText, commandParameters);
        }

        public static DataTable ExecuteTable(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();

            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);

                OleDbDataAdapter ap = new OleDbDataAdapter();
                ap.SelectCommand = cmd;
                DataSet st = new DataSet();
                ap.Fill(st, "Result");
                cmd.Parameters.Clear();
                return st.Tables["Result"];
            }
        }

        public static DataTable ExecuteTable(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, cmdType, cmdText, commandParameters);
            OleDbDataAdapter ap = new OleDbDataAdapter();
            ap.SelectCommand = cmd;
            DataSet st = new DataSet();
            ap.Fill(st, "Result");
            cmd.Parameters.Clear();
            return st.Tables["Result"];
        }

        public static void CacheParameters(string cacheKey, params OleDbParameter[] commandParameters)
        {
            parmCache[cacheKey] = commandParameters;
        }

        public static OleDbParameter[] GetCachedParameters(string cacheKey)
        {
            OleDbParameter[] cachedParms = (OleDbParameter[])parmCache[cacheKey];

            if (cachedParms == null)
                return null;

            OleDbParameter[] clonedParms = new OleDbParameter[cachedParms.Length];

            for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (OleDbParameter)((ICloneable)cachedParms[i]).Clone();

            return clonedParms;
        }

        private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, CommandType cmdType, string cmdText, OleDbParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            cmd.CommandType = cmdType;

            if (cmdParms != null)
            {
                foreach (OleDbParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
    }
}