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OldValue Property [Access 2003 VBA Language Reference]

Office 2003

You can use the OldValue property to determine the unedited value of a bound control. Read-only Variant.

expression.OldValue

expression Required. An expression that returns one of the objects in the Applies To list.

Remarks

The OldValue property contains the unedited data from a bound control and is read-only in all views.

You can access this property only by using a macro or Visual Basic .

The OldValue property can be assigned to a variable by using the following syntax:

OriginalValue = Forms!Customers!AmountPaid.OldValue
		

Microsoft Access uses the OldValue property to store the original value of a bound control. When you edit a bound control on a form, your changes aren't saved until you move to another record. The OldValue property contains the unedited version of the underlying data.

You can provide your own undo capability by assigning the OldValue property setting to a control. The following example shows how you can undo any changes to text box controls on a form:

Private Sub btnUndo_Click()

     Dim ctlTextbox As Control

     For Each ctlTextbox in Me.Controls
     If ctlTextbox.ControlType = acTextBox Then
        ctlTextbox.Value = ctl.OldValue
     End If
     Next ctlTextbox

End Sub
		

If the control hasn't been edited, this code has no effect. When you move to another record, the record source is updated, so the current value and the OldValue property will be the same.

The OldValue property setting has the same data type as the field to which the control is bound.

Example

The following example checks to determine if new data entered in a field is within 10 percent of the value of the original data. If the change is greater than 10 percent, the OldValue property is used to restore the original value. This procedure could be called from the BeforeUpdate event of the control that contains data you want to validate.

Public Sub Validate_Field()

    Dim curNewValue As Currency
    Dim curOriginalValue As Currency
    Dim curChange As Currency
    Dim strMsg As String
    
    curNewValue = Forms!Products!UnitPrice
    curOriginalValue = Forms!Products!UnitPrice.OldValue
    curChange = Abs(curNewValue - curOriginalValue)

    If curChange > (curOriginalValue * .1) Then
        strMsg = "Change is more than 10% of original unit price. " _ 
        & "Restoring original unit price."
        MsgBox strMsg, vbExclamation, "Invalid change."
        Forms!Products!UnitPrice = curOriginalValue
    End If

End Sub
		




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