/// <summary>/// Db4o服务器管理器/// </summary>public static Db4oServerManager Db4oServerManager=new Db4oServerManager("db.db4o");

    public class MvcApplication : System.Web.HttpApplication{/// <summary>/// Db4o服务器管理器/// </summary>public static Db4oServerManager Db4oServerManager;protected void Application_Start(){AreaRegistration.RegisterAllAreas();FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);RouteConfig.RegisterRoutes(RouteTable.Routes);BundleConfig.RegisterBundles(BundleTable.Bundles);Db4oServerManager = new Db4oServerManager(Server.MapPath(System.Configuration.ConfigurationManager.ConnectionStrings["db4o"].ConnectionString));}public override void Dispose(){Db4oServerManager.Dispose();base.Dispose();}}

    <connectionStrings><add name="db4o" connectionString="/App_Data/db.db4o"/></connectionStrings>

                    //无返回值调用方法MvcApplication.Db4oServerManager.Access(q =>{//查找相同ID的对象，以进行更新，否则直接存储将存储为新对象var u = q.Query<ApplicationUser>(t => t.Id == user.Id).First();u.用户信息.名称 = model.DisplayName;//必须明确存储子对象才能得到正确更新，因为默认貌似没有开启级联更新（新建对象存储时会默认自动存储子对象，但更新对象时不会自动更新子对象）
                        q.Store(u.用户信息);});

                    //有返回值调用方法return MvcApplication.Db4oServerManager.AccessAndReturn(q => q.Query<WebSite.Models.ApplicationUser>(t => t.UserName == User.Identity.GetUserName()).First().用户信息.名称)

            using (var dbsa = MvcApplication.Db4oServerManager.CreatAccessor()){var finduser = dbsa.Query<TUser>(q => q.Id == user.Id).FirstOrDefault();dbsa.Delete(finduser);}

    /// <summary>/// Db4o服务器访问器。注意，对数据进行修改后必须释放此对象才能真正的将更改提交到服务器。建议配合using(var dbsa=new Db4oServerAccessor(...)){...}语句使用/// </summary>// ReSharper disable once InconsistentNamingpublic class Db4oServerAccessor : IDisposable{// ReSharper disable once InconsistentNamingprivate IObjectContainer DBContainer { get; set; }/// <summary>/// 构造函数/// </summary>/// <param name="serverManager">Db4o服务器管理器</param>public Db4oServerAccessor(Db4oServerManager serverManager){DBContainer = serverManager.OpenClient();}public void Store(object o){DBContainer.Store(o);}public IDb4oLinqQuery<T> Query<T>(Predicate<T> p){return from T q in DBContainer where p(q) select q;}public IDb4oLinqQuery<T> QueryAll<T>(){return from T q in DBContainer select q;}public int Count<T>(IDb4oLinqQuery<T> collection){return collection.Count();}public int CountAll<T>(){return QueryAll<T>().Count();}public int Count<T>(Predicate<T> p){return Query(p).Count();}public int CountAllByExt<T>(){foreach (var storedClass in DBContainer.Ext().StoredClasses()){if (storedClass.GetName() == typeof(T).FullName) return storedClass.InstanceCount();}return 0;}public void Delete(object o){DBContainer.Delete(o);}public void Delete<T>(Predicate<T> p){foreach (var f in Query<T>(p)){Delete(f);}}#region IDisposable 成员public void Dispose(){DBContainer.Dispose();}#endregion}

    /// <summary>/// Db4o服务器管理器/// </summary>// ReSharper disable once InconsistentNamingpublic class Db4oServerManager : IDisposable{private IObjectServer _db4OServer;private readonly string _dbFilePath;/// <summary>/// 构造函数/// </summary>/// <param name="dbFilePath">数据库文件路径，通常使用Server.MapPath("/xxxx/xx.xx")函数获取到。</param>public Db4oServerManager(string dbFilePath){_dbFilePath = dbFilePath;OpenServer();}private void OpenServer(){IServerConfiguration serverConfig = Db4oClientServer.NewServerConfiguration();_db4OServer = Db4oClientServer.OpenServer(serverConfig, _dbFilePath, 0);}/// <summary>/// 开启一个客户端实例/// </summary>/// <returns>客户端实例</returns>public IObjectContainer OpenClient(){Begin:try{return _db4OServer.OpenClient();}catch{OpenServer();goto Begin;}}/// <summary>/// 创建一个服务器访问器对象。注意，对数据进行修改后必须释放此对象才能真正的将更改提交到服务器。/// </summary>/// <returns>一个服务器访问器对象</returns>public Db4oServerAccessor CreatAccessor(){return new Db4oServerAccessor(this);}/// <summary>/// 创建并访问一个服务器访问器对象。/// </summary>/// <param name="action">对服务器访问器对象的操作行为</param>public void Access(Action<Db4oServerAccessor> action){using (var dba = CreatAccessor()){action(dba);}}/// <summary>/// 创建并访问一个服务器访问器对象，继而获得返回值。/// </summary>/// <param name="action">对服务器访问器对象的操作行为</param>/// <typeparam name="T">返回值类型</typeparam>public T AccessAndReturn<T>(Func<Db4oServerAccessor,T> action){T v = default(T);using (var dba = CreatAccessor()){v= action(dba);//System.Diagnostics.Debug.WriteLine(v.ToString());
            }return v;}#region IDisposable 成员public void Dispose(){_db4OServer.Dispose();}#endregion}