(VS 2017) WPF/MVVM如何回滚对项目集合的更改

如何解决(VS 2017) WPF/MVVM如何回滚对项目集合的更改

我应该实现一个简单的过程来从映射到数据库的数据集合中删除一些项目（例如：车辆，ItemsDC 实体容器的一部分）

'DB Mapping
Public ItemsDC as ItemsDataContext

Sub DeleteVehicles()
  Try
    Dim qryV = From v In ItemsDC.Vehicles Where .... Select v
    If qryV.Count > 0 Then
      For Each vei In qryV
        ItemsDC.Vehicles.DeleteObject(vei)
      Next
    End If
    'Save changes to DB
    ItemsDC.SaveChanges(SaveOptions.AcceptAllChangesAfterSave)
  Catch ex As Exception
    'rollback changes
    RollbackAll()
  End Try 
End Sub

'RollbackAll,rebuilds collection from DB
Sub RollbackAll()
        Dim CString As String = ConfigurationManager.ConnectionStrings("ItemsDataContext").ConnectionString
        entityBuilder = New EntityConnectionStringBuilder(CString)
        Dim sqlBuilder = New SqlConnectionStringBuilder(entityBuilder.ProviderConnectionString)

        sqlBuilder.DataSource = DBName
        sqlBuilder.UserID = AppUser
        sqlBuilder.Password = AppPassword

        entityBuilder.ProviderConnectionString = sqlBuilder.ConnectionString
        ItemsDC = New RappCoaDataContext(entityBuilder.ConnectionString)
End Sub

我意识到 DeleteObject(vei) 似乎是立即提交的；因此，如果引发异常并执行 RollbackAll，则 Vehicles 集合丢失了一些项目。 如何正确回滚更改？