Entity Value Comparison


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Thread: Entity Value Comparison

  1. #1
    Join Date
    May 2004
    Location
    Duluth MN
    Posts
    353

    Entity Value Comparison

    I need to reference the original values of an entity before doing a SaveChanges(). Is the value in the store available and what is the syntax to access it?

    Example: I have an Employee entity and change the Hours of the employee. How can I determine, before I implement the SaveChanges() that Hours has been modified?

    ...joe

  2. #2
    Join Date
    May 2004
    Location
    Duluth MN
    Posts
    353
    Figured out a solution:

    Code:
    Sub CheckModifiedValues(ByVal Context As ObjectContext)
            Try
                'Get all objects modified
                Dim Changes As IEnumerable(Of ObjectStateEntry) = Context.ObjectStateManager.GetObjectStateEntries(EntityState.Modified)
                If Changes.Count > 0 Then
                    'Loop through changed objects
                    For Each Obj In Changes
                        'get the properties modified for the object
                        Dim ModifiedProperties As IEnumerable(Of String) = Obj.GetModifiedProperties
                        If ModifiedProperties.Count > 0 Then
                            For Each prop As String In ModifiedProperties
                                'these will error if you pass through a property that was not modified - thus the GetModifiedProperties
                                Dim strOrg As String = Obj.OriginalValues(prop).ToString
                                Dim strMod As String = Obj.CurrentValues(prop).ToString
                                MessageBox.Show("Current " & prop & ": " & strMod & " Original " & prop & ": " & strOrg)
                            Next
                        End If
                    Next
                End If
            Catch ex As Exception
                MessageBox.Show(ex.Message)
            End Try
        End Sub

    ...joe

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