設定項目をAccessに保存・取得するシングルトン

かなウェルや波佐見弁利で、設定項目を永続化したいと思って作ったクラス。
Accessに保存する中間クラスとした。
キャッシュ機能つき。

Accessのテーブルは以下のよう。

settingsSingleton：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ABCS.DAOs;
using ABCS.App_Data;

namespace 波佐見弁利v2.DAOs
{
    class settingsSingleton
    {
        #region //設定のキー
        public static string KeyUsePredictSocialIME = "KeyUsePredictSocialIME";
        public static string KeyUseNormalSocialIME = "KeyUseNormalSocialIME";
        public static string KeyUsePredictVJE = "KeyUsePredictVJE";
        public static string KeyUseNormalVJE = "KeyUseNormalVJE";
        #endregion

        #region //定数
        public static string TRUE = "true";
        public static string FALSE = "false";
        #endregion

        public class values
        {
            public int intValue = 0;
            public string strgValue = "";
            public values(int intvalue, string strgvalue)
            {
                this.intValue = intvalue;
                this.strgValue = strgvalue;
            }
        }
        private static Dictionary cache_ = new Dictionary();
        private static settingsSingleton sigleton_ = new settingsSingleton();

        settingsSingleton()
        {
        }

        public settingsSingleton getInstance()
        {
            return settingsSingleton.sigleton_;
        }

        public static bool isExistsIntValue(string strgKey)
        {
            Dictionary c = settingsSingleton.cache_;

            if (c.ContainsKey(strgKey))
            {

                values v = c[strgKey];
                if (v != null)
                {
                    if (v.intValue != Int32.MinValue)
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }
        public static bool isExistsStringValue(string strgKey)
        {
            Dictionary c = settingsSingleton.cache_;

            if (c.ContainsKey(strgKey))
            {
                values v = c[strgKey];
                if (v != null)
                {
                    if (v.strgValue != null)
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }

        public static void getValue(string strgKey, out int intValue)
        {
            intValue = 0;

            if (!settingsSingleton.isExistsIntValue(strgKey))
            {
                //キャッシュになし
                //DBから読み込む
                using (DAOContext con = new DAOContext(AccessConString.mainConString))
                {
                    con.OpenConnection();
                    settingsDAO dao = new settingsDAO(con);

                    dao.selectSetting(strgKey, out intValue);

                    con.CloseConnection();

                    settingsSingleton.cache_[strgKey] = new values(intValue, null);
                }
            }
            else
            {
                //キャッシュにあり
                //キャッシュの値を返す
                values v = settingsSingleton.cache_[strgKey];
                intValue = v.intValue;
            }
        }
        public static void getValue(string strgKey, out string strgValue)
        {
            strgValue = "";

            if (!settingsSingleton.isExistsStringValue(strgKey))
            {
                //キャッシュになし
                //DBから読み込む
                using (DAOContext con = new DAOContext(AccessConString.mainConString))
                {
                    con.OpenConnection();
                    settingsDAO dao = new settingsDAO(con);

                    dao.selectSetting(strgKey, out strgValue);

                    con.CloseConnection();

                    settingsSingleton.cache_[strgKey] = new values(Int32.MinValue, strgValue);
                }
            }
            else
            {
                //キャッシュにあり
                //キャッシュの値を返す
                values v = settingsSingleton.cache_[strgKey];
                strgValue = v.strgValue;
            }
        }

        public static bool isEqualsIntValue(values v, int intValue)
        {
            if (v != null)
            {
                if (v.intValue == intValue)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }
        public static bool isEqualsStringValue(values v, string strgValue)
        {
            if (v != null)
            {
                if (v.strgValue.Equals(strgValue))
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }
        public static void setValue(string strgKey, int intValue)
        {
            using (DAOContext con = new DAOContext(AccessConString.mainConString))
            {
                con.OpenConnection();
                settingsDAO dao = new settingsDAO(con);
                dao.mergeSettings(strgKey, intValue);
                con.CloseConnection();
            }
            settingsSingleton.cache_[strgKey] = new values(intValue, null);
        }
        public static void setValue(string strgKey, string strgValue)
        {
            using (DAOContext con = new DAOContext(AccessConString.mainConString))
            {
                con.OpenConnection();
                settingsDAO dao = new settingsDAO(con);
                dao.mergeSettings(strgKey, strgValue);
                con.CloseConnection();
            }
            settingsSingleton.cache_[strgKey] = new values(Int32.MinValue, strgValue);
        }
    }
}

シングルトンで使っているDAO。
settingsDAO：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using ABCS.DAOs;

namespace ABCS.DAOs
{
    class settingsDAO : MyDAOBase
    {
        public settingsDAO(DAOContext con) : base(con) { }

        public void selectSetting(string strgKey, out int intValue)
        {
            string sql = @"select *
                            from settings
                            where
                                SETTINGKEY like @pkey";

            this.ClearParameters();
            this.AddParameter("pkey", DbType.String, strgKey);

            DataTable tbl = base.GetTable(sql);

            if (tbl.Rows.Count > 0)
            {
                int ret = 0;
                int.TryParse(tbl.Rows[0]["INTVALUE"].ToString(), out ret);
                intValue = ret;
            }
            else
            {
                intValue = 0;
            }
        }

        public void selectSetting(string strgKey, out string strgValue)
        {
            string sql = @"select *
                            from settings
                            where
                                SETTINGKEY like @pkey";

            this.ClearParameters();
            this.AddParameter("pkey", DbType.String, strgKey);

            DataTable tbl = base.GetTable(sql);

            if (tbl.Rows.Count > 0)
            {
                strgValue = tbl.Rows[0]["TEXTVALUE"].ToString();
            }
            else
            {
                strgValue = "";
            }
        }

        public bool isExistSetting(string strgKey)
        {
            string sql = @"select *
                            from settings
                            where
                                SETTINGKEY like @pkey";

            this.ClearParameters();
            this.AddParameter("pkey", DbType.String, strgKey);

            DataTable tbl = base.GetTable(sql);

            if (tbl.Rows.Count > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }



        #region //数値設定

        public int updateDate(string strgKey, int intValue)
        {
            string sql = @"update settings
                            set
                                INTVALUE = @pintvalue
                            where
                                SETTINGKEY like @pkey";

            this.ClearParameters();
            this.AddParameter("pintvalue", DbType.Int32, intValue);
            this.AddParameter("pkey", DbType.String, strgKey);

            return base.ExecuteNonQuery(sql);
        }

        public int insertNew(string strgKey, int intValue)
        {
            string sql = @"insert into
                            settings(
                                 SETTINGKEY
                                ,INTVALUE
                            )
                            values(
                                 @pkey
                                ,@pintvalue
                            )";

            this.ClearParameters();
            this.AddParameter("pkey", DbType.String, strgKey);
            this.AddParameter("pintvalue", DbType.Int32, intValue);

            return base.ExecuteNonQuery(sql);
        }

        public int mergeSettings(string strgKey, int intValue)
        {
            if (this.isExistSetting(strgKey))
            {
                return this.updateDate(strgKey, intValue);
            }
            else
            {
                return this.insertNew(strgKey, intValue);
            }
        }

        #endregion

        #region //文字設定

        public int updateDate(string strgKey, string strgValue)
        {
            string sql = @"update settings
                            set
                                TEXTVALUE = @ptextvalue
                            where
                                SETTINGKEY like @pkey";

            this.ClearParameters();
            this.AddParameter("ptextvalue", DbType.String, strgValue);
            this.AddParameter("pkey", DbType.String, strgKey);

            return base.ExecuteNonQuery(sql);
        }

        public int insertNew(string strgKey, string strgValue)
        {
            string sql = @"insert into
                            settings(
                                SETTINGKEY
                                ,TEXTVALUE
                            )
                            values(
                                @ppkey
                                ,@pptextvalue
                            )";

            this.ClearParameters();
            this.AddParameter("ppkey", DbType.String, strgKey);
            this.AddParameter("pptextvalue", DbType.String, strgValue);

            return base.ExecuteNonQuery(sql);
        }

        public int mergeSettings(string strgKey, string strgValue)
        {
            if (this.isExistSetting(strgKey))
            {
                return this.updateDate(strgKey, strgValue);
            }
            else
            {
                return this.insertNew(strgKey, strgValue);
            }
        }

        #endregion
    }
}

上のDAOのベースクラス。
MyDAOBase：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;

namespace ABCS.DAOs
{
    public class DAOContext : IDisposable
    {
        private DbConnection con_ = null;
        private DbProviderFactory fac_ = null;
        private DbTransaction tran_ = null;
        public DbConnection Connection {
            get
            {
                return this.con_;
            }
            private set
            {
                this.con_ = value;
            }
        }
        public DbProviderFactory Factory {
            get
            {
                return this.fac_;
            }
            private set
            {
                this.fac_ = value;
            }
        }
        public DbTransaction Transaction { 
            get
            {
                return this.tran_;
            }
            private set
            {
                this.tran_ = value;
            }
        }

        public DAOContext()
            : this("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|abc.mdb")
        {
        }

        public DAOContext(string connectionString)
            : this("System.Data.OleDb", connectionString)
        {
        }

        public DAOContext(string providerName, string connectionString)
        {
            if (providerName == null) throw new ArgumentNullException("providerName");
            if (connectionString == null) throw new ArgumentNullException("connectionString");

            this.Factory = DbProviderFactories.GetFactory(providerName);
            this.Connection = this.Factory.CreateConnection();
            this.Connection.ConnectionString = connectionString;
        }

        public void OpenConnection()
        {
            if (this.Connection == null)
                throw new InvalidOperationException("Object is diposed.");

            if (this.Connection.State == ConnectionState.Closed)
                this.Connection.Open();
        }

        public void CloseConnection()
        {
            if (this.Connection == null)
                throw new InvalidOperationException("Object is diposed.");

            if (this.Connection.State == ConnectionState.Open)
                this.Connection.Close();
        }

        public void BeginTransaction(IsolationLevel isolationLevel)
        {
            if (this.Transaction != null)
                throw new InvalidOperationException("There is already a transaction.");

            this.OpenConnection();
            this.Transaction = this.Connection.BeginTransaction(isolationLevel);
        }

        public void CommitTransaction()
        {
            if (this.Transaction == null)
                throw new InvalidOperationException("There is no transaction.");

            this.Transaction.Commit();
            this.Transaction = null;
        }

        public void RollbackTransaction()
        {
            if (this.Transaction == null)
                throw new InvalidOperationException("There is no transaction.");

            this.Transaction.Rollback();
            this.Transaction = null;
        }

        public void Dispose()
        {
            this.Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                try
                {
                    if (this.Transaction != null)
                    {
                        this.RollbackTransaction();
                        this.Transaction = null;
                    }
                }
                finally
                {
                    if (this.Connection != null)
                    {
                        this.Connection.Dispose();
                        this.Connection = null;
                    }
                }
            }
        }
    }

    public class MyDAOBase
    {
        private readonly List parameters = new List();

        private DAOContext context_ = null;

        public DAOContext Context {
            get
            {
                return this.context_;
            }
            private set
            {
                this.context_ = value;
            }
        }

        public IList Parameters
        {
            get { return this.parameters; }
        }


        public MyDAOBase(DAOContext context)
        {
            if (context == null) throw new ArgumentNullException("context");
            this.Context = context;
        }

        public void ClearParameters()
        {
            this.parameters.Clear();
        }
        public void AddParameter(string parameterName, DbType dbType, object value)
        {
            DbParameter p = this.Context.Factory.CreateParameter();
            p.ParameterName = parameterName;
            p.DbType = dbType;
            p.Value = value;
            this.parameters.Add(p);
        }

        protected void ExecuteCommand(string commandText, IEnumerable parameters,
            Action action)
        {
            DbCommand command = this.Context.Factory.CreateCommand();
            command.CommandText = commandText;
            command.Connection = this.Context.Connection;
            command.Transaction = this.Context.Transaction;
            foreach (DbParameter parameter in parameters)
                command.Parameters.Add(parameter);
            action(command);
        }

        protected int ExecuteNonQuery(string commandText, IEnumerable parameters)
        {
            int count = 0;
            this.ExecuteCommand(commandText, parameters, delegate(DbCommand command){
                count = command.ExecuteNonQuery();
            });
            return count;
        }

        protected int ExecuteNonQuery(string commandText)
        {
            return this.ExecuteNonQuery(commandText, this.parameters);
        }

        protected DataTable GetTable(string commandText, IEnumerable parameters)
        {
            DataTable table = new DataTable();
            this.ExecuteCommand(commandText, parameters, delegate(DbCommand command)
            {
                using (DbDataReader reader = command.ExecuteReader())
                {
                    table.Load(reader);
                }
            });
            return table;
        }

        protected DataTable GetTable(string commandText)
        {
            return this.GetTable(commandText, this.Parameters);
        }
    }
}

Accessの接続文字列を保持するクラス。
AccessConString：

using System;
using System.Collections.Generic;
using System.Text;

namespace ABCS.App_Data
{
    public class AccessConString
    {
        public static readonly string ConString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|App_Data\\abc.mdb";
        public static readonly string mainConString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|App_Data\\main.mdb";
    }
}