ACC: How to Automatically Detect If a Form Is Being Edited

MORE INFORMATION

When Microsoft Access displays a pencil symbol in the record selector, the record is being edited but has not yet been saved. When Microsoft Access displays a triangle symbol in the record selector, the record has been saved and is not being edited. Note that if the form's RecordSelector property is set to No, these symbols are not displayed.

There are two methods that you can use to automatically run code when a form's Edit mode changes:

• Use the form's Timer event to check the form's Dirty property periodically to see if the Edit mode has changed.
• Use the Dirty property in an expression on the form to run a function when the Edit mode changes.

The following examples demonstrate how to use these techniques to automatically enable or disable an Undo Record button, depending on a form's Edit mode.

Method 1: Using the Form's Timer Event

1. Open the sample database Northwind.mdb (or NWIND.MDB in version 2.0).
2. Open the Employees form in Design view.
3. Use the Command Button Wizard to create an Undo Record button on the form.
4. Change the Undo Record button's properties to match the following:

   Name: btnUndo Enabled: No

5. Set the form's TimerInterval property to:

   1000

6. Set the form's OnTimer property to the following event procedure:

         Private Sub Form_Timer()
             Static bFlag As Boolean
             If Me.Dirty Then
                 If Not bFlag Then
                     Me!btnUndo.Enabled = True
                     bFlag = True
                 End If
             Else
                 If bFlag Then
                    Me!FirstName.SetFocus
                    Me!btnUndo.Enabled = False
                    bFlag = False
                 End If
             End If
         End Sub
   						

7. View the form in Form view. Note that the Undo Record button is unavailable.
8. Modify any field in the current record, and then press the TAB key. Note that the Undo Record button becomes available.
9. Press the ESC key twice (or click Undo on the Edit menu) to undo your changes. Note that the Undo Record button becomes unavailable.

Method 2: Using the Dirty Property in an Expression

1. Follow steps 1 through 4 in Method 1.
2. Add a new text box with the following properties to the form:

         Name: txtEditModeChange
         ControlSource: =[Form].[Dirty] & EditModeChange([Form])
         Visible: No
   						

3. On the View menu, click Code.
4. Create the following function in the module, and then close the module:

         Function EditModeChange (F As Form) As Variant
            If F.Dirty Then
               F!btnUndo.Enabled = True
            Else
               F!btnUndo.Enabled = False
            End If
         End Function
   						

5. Set the form's AfterUpdate property to the following event procedure:

         Sub Form_AfterUpdate ()
            Me!txtEditModeChange.Requery
         End Sub
   						

6. Follow steps 7 through 9 in Method 1 to test this method.