EntityContainer 类

参考

定义

命名空间:: System.Data.Metadata.Edm

程序集:: System.Data.Entity.dll

重要

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表示概念模型中的实体容器。 EntityContainer 是实体集和关联集的逻辑分组。

public ref class EntityContainer sealed : System::Data::Metadata::Edm::GlobalItem

public sealed class EntityContainer : System.Data.Metadata.Edm.GlobalItem

type EntityContainer = class
    inherit GlobalItem

Public NotInheritable Class EntityContainer
Inherits GlobalItem

继承: Object

MetadataItem

GlobalItem
EntityContainer

示例

下面的代码示例演示如何利用连接获取元数据工作区，然后使用该元数据工作区在指定的数据模型中检索有关实体容器的信息。请注意，元数据工作区是一个为检索元数据提供支持的运行时服务组件。

该代码示例使用 CSpace 和 SSpace 指定模型。 CSpace 表示概念性模型的默认名称。 SSpace 表示存储模型的默认名称。

方法 GetEntityContainers 获取实体容器的集合，然后循环访问该集合以获取指定容器中每个实体集和关联集。代码示例使用 AdventureWorks 模型。

using System;  
using System.Data;  
using System.Data.EntityClient;  
using System.Data.Metadata.Edm;  
using System.Collections.ObjectModel;  

class GetEntityContainerExample  
{  
  static void Main()  
  {  
    try  
    {  
       // Establish a connection to the underlying data provider by   
       // using the connection string specified in the config file.  
       using (EntityConnection connection =  
          new EntityConnection("Name=AdventureWorksEntities"))  
       {  
         // Open the connection.  
         connection.Open();  

         // Access the metadata workspace.  
         MetadataWorkspace workspace =   
            connection.GetMetadataWorkspace();  

         // Get the entity containers in the conceptual model.  
         GetEntityContainers(workspace, DataSpace.CSpace);  

         // Get the entity containers in the storage model.  
             GetEntityContainers(workspace, DataSpace.SSpace);  
       }  
    }  
    catch (MetadataException exceptionMetadata)  
    {  
      Console.WriteLine("MetadataException: {0}",   
                       exceptionMetadata.Message);  
    }  
    catch (System.Data.MappingException exceptionMapping)  
    {  
      Console.WriteLine("MappingException: {0}",  
                       exceptionMapping.Message);  
    }  
  }  

  public static void GetEntityContainers(  
      MetadataWorkspace workspace, DataSpace model)  
  {  
    // Get a collection of the entity containers.  
    ReadOnlyCollection<EntityContainer> containers =   
         workspace.GetItems<EntityContainer>(model);  

    // Iterate through the collection to get each entity container.  
    foreach (EntityContainer container in containers)  
    {  
       Console.WriteLine("EntityContainer Name: {0} ",   
                        container.Name);  

       // EntitySetBase is a super type for   
       // EntitySets and RelationshipSets.   
       // Iterate through the collection to get each EntitySetBase.  
       foreach (EntitySetBase baseSet in container.BaseEntitySets)  
       {  
          // Check if this instance is an EntitySet.  
          if (baseSet is EntitySet)  
          {  
             Console.WriteLine(  
                "  EntitySet Name: {0} , EntityType Name: {1} ",  
                baseSet.Name, baseSet.ElementType.FullName);  
          }  

         // RelationshipSet is a super type for AssociationSet.  
         // Check if this instance is an AssociationSet.  
         if (baseSet is AssociationSet)  
         {  
            Console.WriteLine(  
               "  AssociationSet Name: {0} , " +  
               "AssociationType Name: {1} ",  
                baseSet.Name, baseSet.ElementType.FullName);  

            // Get the AssociationSet.  
            AssociationSet associationSet =   
                  baseSet as AssociationSet;  

            // Iterate through the collection to get   
            // each AssociatedSetEnd.  
            foreach (AssociationSetEnd end in   
               associationSet.AssociationSetEnds)  
            {  
               Console.WriteLine(  
                  "   EntitySet Name: {0} , Name: {1} ",  
                  end.EntitySet, end.Name);  
            }  
         }  
      }  
    }  
  }  
}

Imports System  
Imports System.Collections.ObjectModel  
Imports System.Data  
Imports System.Data.EntityClient  
Imports System.Data.Metadata.Edm  

Class GetEntityContainerExample  
  Public Shared Sub Main()  
    Try  
      ' Establish a connection to the underlying data provider by   
      ' using the connection string specified in the config file.  
      Using connection As EntityConnection = _  
        New EntityConnection("Name=AdventureWorksEntities")  

        ' Open the connection.  
        connection.Open()  

        ' Access the metadata workspace.  
        Dim workspace As MetadataWorkspace = _  
           connection.GetMetadataWorkspace  

        ' Get the entity containers in the conceptual model.  
        GetEntityContainers(workspace, DataSpace.CSpace)  

        ' Get the entity containers in the storage model.  
        GetEntityContainers(workspace, DataSpace.SSpace)  
      End Using  
    Catch exceptionMetadata As MetadataException  
       Console.WriteLine("MetadataException: {0}", _  
          exceptionMetadata.Message)  
    Catch exceptionMapping As MappingException  
       Console.WriteLine("MappingException: {0}", _  
          exceptionMapping.Message)  
     End Try  
  End Sub  

  Public Shared Sub GetEntityContainers( _  
    ByVal workspace As MetadataWorkspace, ByVal model As DataSpace)  

    ' Get a collection of the entity containers.  
    Dim containers As ReadOnlyCollection(Of EntityContainer) = _  
       workspace.GetItems(Of EntityContainer)(model)  

    ' Iterate through the collection to get each entity container.  
    Dim container As EntityContainer  
    For Each container In containers  
      Console.WriteLine("EntityContainer Name: {0} ", container.Name)  

      ' EntitySetBase is a super type for   
      ' EntitySets and RelationshipSets.   
      ' Iterate through the collection to get each EntitySetBase.  
      Dim baseSet As EntitySetBase  
      For Each baseSet In container.BaseEntitySets  
         ' Check if this instance is an EntitySet.  
         If TypeOf baseSet Is EntitySet Then  
           Console.WriteLine( _  
              "  EntitySet Name: {0} , EntityType Name: {1} ", _  
              baseSet.Name, baseSet.ElementType.FullName)  
          End If  

          ' RelationshipSet is a super type for AssociationSet.  
          ' Check if this instance is an AssociationSet.  
          If TypeOf baseSet Is AssociationSet Then  
            Console.WriteLine( _  
              "  AssociationSet Name: {0} , " + _  
              "AssociationType Name: {1} ", _  
              baseSet.Name, baseSet.ElementType.FullName)  

            ' Get the AssociationSet.  
            Dim associationSet As AssociationSet = _  
               TryCast(baseSet, AssociationSet)  

            ' Iterate through the collection to get   
            '  each AssociatedSetEnd.  
            Dim endMember As AssociationSetEnd  
            For Each endMember In associationSet.AssociationSetEnds  
              Console.WriteLine( _  
                 "   EntitySet Name: {0} , Name: {1} ", _  
                 endMember.EntitySet, endMember.Name)  
            Next  
          End If  
      Next  
    Next  
  End Sub  
End Class

注解

在概念级别上，EntityContainer 类表示将映射到存储元数据架构中的数据库对象的容器。在存储级别上，EntityContainer 类描述了为基于模型构建的应用程序持久保存数据的表和/或键关系。有关概念模型中的实体容器的详细信息，请参阅实体容器。

属性

BaseEntitySets	获取此 EntityContainer 包括的实体集和关联集的列表。
BuiltInTypeKind	获取此 EntityContainer 的内置类型种类。
Documentation	获取或设置与此类型关联的文档。 (继承自 MetadataItem)
FunctionImports	指定 EdmFunction 元素的集合。每个函数都包含数据库中存在或映射到实体及其属性的等效 `CommandText` 存储过程的详细信息。
MetadataProperties	获取当前类型的属性列表。 (继承自 MetadataItem)
Name	获取此 EntityContainer 的名称。

方法

Equals(Object)	确定指定对象是否等于当前对象。 (继承自 Object)
GetEntitySetByName(String, Boolean)	使用实体集的指定名称返回一个 EntitySet 对象。
GetHashCode()	作为默认哈希函数。 (继承自 Object)
GetRelationshipSetByName(String, Boolean)	使用关系集的指定名称返回一个 RelationshipSet 对象。
GetType()	获取当前实例的 Type。 (继承自 Object)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
ToString()	返回此 EntityContainer 的名称。
TryGetEntitySetByName(String, Boolean, EntitySet)	使用实体集的指定名称返回一个 EntitySet 对象。
TryGetRelationshipSetByName(String, Boolean, RelationshipSet)	使用关系集的指定名称返回一个 RelationshipSet 对象。

适用于

EntityContainer 类

定义

示例

注解

属性

方法

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