2

我需要在运行时使用实体框架进行连接和架构更改。

我尝试了以下代码：发布

我正在使用该代码：

        public EntityConnection SetCurrentEntityConnection(string schemaName, string databaseIPAddress, int databasePort, string userName, string password, string model)
    {
        XmlReader[] MappingReader = new XmlReader[] { XmlReader.Create(Assembly.GetExecutingAssembly().GetManifestResourceStream(model + ".msl")) };
        XmlReader[] ConceptualReader = new XmlReader[] { XmlReader.Create(Assembly.GetExecutingAssembly().GetManifestResourceStream(model + ".csdl")) };

        var StorageReader = XmlReader.Create(Assembly.GetExecutingAssembly().GetManifestResourceStream(model + ".ssdl"));
        XNamespace StorageNS = "http://schemas.microsoft.com/ado/2009/02/edm/ssdl";

        var StorageXml = XElement.Load(StorageReader);

        foreach (var EntitySet in StorageXml.Descendants(StorageNS + "EntitySet"))
        {
            var SchemaAttribute = EntitySet.Attributes("Schema").FirstOrDefault();
            if (SchemaAttribute != null)
                SchemaAttribute.SetValue(schemaName);
        }
        StorageXml.CreateReader();

        var Workspace = new MetadataWorkspace();
        StoreItemCollection StorageCollection = new StoreItemCollection(new XmlReader[] { StorageXml.CreateReader() });
        EdmItemCollection ConceptualCollection = new EdmItemCollection(ConceptualReader);
        StorageMappingItemCollection MappingCollection = new StorageMappingItemCollection(ConceptualCollection, StorageCollection, MappingReader);
        Workspace.RegisterItemCollection(ConceptualCollection);
        Workspace.RegisterItemCollection(StorageCollection);
        Workspace.RegisterItemCollection(MappingCollection);

        ///
        /// Adjust the connection string
        /// 
        var ConnectionData = new EntityConnectionStringBuilder();
        ConnectionData.Provider = "Oracle.ManagedDataAccess.Client";
        ConnectionData.Metadata = "metadata=res://*/Model.Model.csdl|res://*/Model.Model.ssdl|res://*/Model.Model.msl";
        ConnectionData.Name = "Entities";

        /// Build the connection string (using Oracle EZ Connection string)
        string conn = "data source=" + userName + "/" + password + "@" + databaseIPAddress + ":" + databasePort + "/" + schemaName ;

        ConnectionData.ProviderConnectionString = conn;


        var Connection = DbProviderFactories.GetFactory(ConnectionData.Provider).CreateConnection();
        Connection.ConnectionString = ConnectionData.ProviderConnectionString;

        new EntityConnection(Workspace, Connection);
    }

我遇到了两个问题：

问题 1：foreach 循环找不到任何 EntitySet 来更改架构。

问题 2：我不知道如何在我的 EF 应用程序中使用新创建的 EntityConnection。我通常使用：

Entity dbContext = new Entity();

并开始对我的 dbContext 进行查询，但我不知道如何处理 EntityConnection 以及应该如何处理它。那么，新创建的 EntityConnection 和原来的 DbContext 之间是什么关系。

顺便说一句，我正在使用 DatabaseFirst for Oracle。DMDX 不会生成带有连接参数的实体构造函数。

谢谢你的帮助。这真让我抓狂...

4

0 回答 0