如何：附加相关对象（实体框架）

本主题提供有关如何将相关对象附加到对象上下文的示例。有关更多信息，请参见附加对象（实体框架）。在重新构造使用 XML 序列化进行过序列化的对象图时使用此过程。

本主题中的示例基于 Adventure Works 销售模型。若要运行本示例中的代码，必须已将 AdventureWorks 销售模型添加到您的项目中，并将项目配置为使用 实体框架。为此，请完成如何：手动配置实体框架项目和如何：手动定义实体数据模型（实体框架） 中的过程。

示例

本示例将已分离的 SalesOrderDetail 对象的集合与已分离的 SalesOrderHeader 对象附加到对象上下文，然后定义 SalesOrderHeader 对象与每个 SalesOrderDetail 对象之间的关系。

Private Shared Sub AttachRelatedObjects( _
ByVal currentContext As ObjectContext, _
ByVal detachedOrder As SalesOrderHeader, _
ByVal detachedItems As List(Of SalesOrderDetail))
    Try
        ' Attach the root detachedOrder object to the supplied context.
        currentContext.Attach(detachedOrder)

        ' Attach each detachedItem to the context, and define each relationship
        ' by attaching the attached SalesOrderDetail object to the EntityCollection on 
        ' the SalesOrderDetail navigation property of the now attached detachedOrder.
        For Each item As SalesOrderDetail In detachedItems
            currentContext.Attach(item)
            detachedOrder.SalesOrderDetail.Attach(item)
        Next

    Catch ex As InvalidOperationException
        Console.WriteLine(ex.ToString())
    End Try
End Sub

private static void AttachRelatedObjects(
    ObjectContext currentContext,
    SalesOrderHeader detachedOrder,
    List<SalesOrderDetail> detachedItems)
{
    try
    {
        // Attach the root detachedOrder object to the supplied context.
        currentContext.Attach(detachedOrder);

        // Attach each detachedItem to the context, and define each relationship
        // by attaching the attached SalesOrderDetail object to the EntityCollection on 
        // the SalesOrderDetail navigation property of the now attached detachedOrder.
        foreach (SalesOrderDetail item in detachedItems)
        {
            currentContext.Attach(item);
            detachedOrder.SalesOrderDetail.Attach(item);
        }
    }
    catch (InvalidOperationException ex)
    {
        Console.WriteLine(ex.GetType().ToString() + ": " + ex.ToString());
    }
}

本示例将已分离的 SalesOrderDetail 对象的集合添加到已分离的 SalesOrderHeader 对象，然后将此对象图附加到对象上下文。

Private Shared Sub AttachObjectGraph( _
ByVal currentContext As ObjectContext, _
ByVal detachedOrder As SalesOrderHeader, _
ByVal detachedItems As List(Of SalesOrderDetail))
    Try
        ' Define the relationships by adding each SalesOrderDetail 
        ' object in the detachedItems List<SalesOrderDetail> collection to the 
        ' EntityCollection on the SalesOrderDetail navigation property of detachedOrder.
        For Each item As SalesOrderDetail In detachedItems
            detachedOrder.SalesOrderDetail.Add(item)
        Next

        ' Attach the object graph to the supplied context.
        currentContext.Attach(detachedOrder)

    Catch ex As InvalidOperationException
        Console.WriteLine(ex.ToString())
    End Try
End Sub

private static void AttachObjectGraph(
    ObjectContext currentContext,
    SalesOrderHeader detachedOrder, 
    List<SalesOrderDetail> detachedItems)
{
        try
        {
            // Define the relationships by adding each SalesOrderDetail 
            // object in the detachedItems List<SalesOrderDetail> collection to the 
            // EntityCollection on the SalesOrderDetail navigation property of detachedOrder.
            foreach (SalesOrderDetail item in detachedItems)
            {
                detachedOrder.SalesOrderDetail.Add(item);
            }

            // Attach the object graph to the supplied context.
            currentContext.Attach(detachedOrder);
        }
        catch (InvalidOperationException ex)
        {
            Console.WriteLine(ex.GetType().ToString() + ": " + ex.ToString());
        }
}

另请参见

概念

序列化对象（实体框架）
Web 服务和实体数据模型（应用程序方案）

其他资源

管理对象上下文（实体框架）
使用对象（实体框架任务）