db4o助手 do4oHelper

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

using Db4objects.Db4o;//使用的是db4o7.12 自己添加dll引用

namespace DB4OHelper
{
    public class dbHelper
    {
        string _dbFilePath = string.Empty;

        public IObjectContainer db = null;

        #region 
// 1IList <Pilot> result = db.Query<Pilot> (delegate(Pilot pilot) {
//2    return pilot.Points > 99
//3        && pilot.Points < 199
//4        || pilot.Name == "Rubens Barrichello";
//5});
        #endregion

        public dbHelper(string dbFilePath)
        {
            _dbFilePath = dbFilePath;


        }

        private void openDatabase()
        {
            db = Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), _dbFilePath);
        }

        private void closeDatabase()
        {
            db.Close();
        }

        public void save<EntityType>(EntityType EntityObj)
        {

            openDatabase();

            try
            {

                db.Store(EntityObj);
            }
            finally
            {
                closeDatabase();
            }
        }

        /// <summary>
        /// 查询全部数据
        /// </summary>
        /// <typeparam name="ClassType"></typeparam>
        /// <returns></returns>
        public IList<ClassType> Query<ClassType>()
        {
            // IObjectContainer mydb = Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), _dbFilePath);
            openDatabase();
            try
            {
                IObjectSet resoult = db.QueryByExample(typeof(ClassType));


                return convertDataSet<ClassType>(resoult);
            }
            finally
            {
                closeDatabase();
                // mydb.Close();
            }
        }

        /// <summary>
        /// 条件查询
        /// </summary>
        /// <typeparam name="ClassType"></typeparam>
        /// <param name="parmObj"></param>
        /// <returns></returns>
        public IList<ClassType> Query<ClassType>(ClassType parmObj)
        {
            openDatabase();
            try
            {
                IObjectSet resoutl = db.QueryByExample(parmObj);
                return convertDataSet<ClassType>(resoutl);
            }
            finally
            {
                closeDatabase();
            }
        }

        public IList<T> convertDataSet<T>(IObjectSet ListSet)
        {
            List<T> resoult = new List<T>();
            while (ListSet.HasNext())
            {
                T obj = (T)ListSet.Next();
                resoult.Add(obj);
            }

            return resoult;
        }

    }

    

}