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VB.NET ObjectStateManager.TryGetObjectStateEntry方法代码示例

本文整理汇总了VB.NET中System.Data.Objects.ObjectStateManager.TryGetObjectStateEntry方法的典型用法代码示例。如果您正苦于以下问题:VB.NET ObjectStateManager.TryGetObjectStateEntry方法的具体用法?VB.NET ObjectStateManager.TryGetObjectStateEntry怎么用?VB.NET ObjectStateManager.TryGetObjectStateEntry使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在System.Data.Objects.ObjectStateManager的用法示例。


在下文中一共展示了ObjectStateManager.TryGetObjectStateEntry方法的2个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的VB.NET代码示例。

示例1: AdventureWorksEntities

Dim orderId As Integer = 43680

Using context As New AdventureWorksEntities()
    Dim objectStateManager As ObjectStateManager = context.ObjectStateManager
    Dim stateEntry As ObjectStateEntry = Nothing

    Dim order = (From o In context.SalesOrderHeaders
        Where o.SalesOrderID = orderId
        Select o).First()

    ' Attempts to retrieve ObjectStateEntry for the given EntityKey. 
    Dim isPresent As Boolean = objectStateManager.TryGetObjectStateEntry(DirectCast(order, IEntityWithKey).EntityKey, stateEntry)
    If isPresent Then
        Console.WriteLine("The entity was found")
    End If
End Using
开发者ID:VB.NET开发者,项目名称:System.Data.Objects,代码行数:16,代码来源:ObjectStateManager.TryGetObjectStateEntry

示例2: ApplyItemUpdates

Private Shared Sub ApplyItemUpdates(ByVal originalItem As SalesOrderDetail, ByVal updatedItem As SalesOrderDetail)
    Using context As New AdventureWorksEntities()
        context.SalesOrderDetails.Attach(updatedItem)
        ' Check if the ID is 0, if it is the item is new. 
        ' In this case we need to chage the state to Added. 
        If updatedItem.SalesOrderDetailID = 0 Then
            ' Because the ID is generated by the database we do not need to 
            ' set updatedItem.SalesOrderDetailID. 
            context.ObjectStateManager.ChangeObjectState(updatedItem, System.Data.EntityState.Added)
        Else
            ' If the SalesOrderDetailID is not 0, then the item is not new 
            ' and needs to be updated. Because we already added the 
            ' updated object to the context we need to apply the original values. 
            ' If we attached originalItem to the context 
            ' we would need to apply the current values: 
            ' context.ApplyCurrentValues("SalesOrderDetails", updatedItem); 
            ' Applying current or original values, changes the state 
            ' of the attached object to Modified. 
            context.ApplyOriginalValues("SalesOrderDetails", originalItem)
        End If
        context.SaveChanges()
    End Using
End Sub
开发者ID:VB.NET开发者,项目名称:System.Data.Objects,代码行数:23,代码来源:ObjectStateManager.TryGetObjectStateEntry


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