HOW TO: Automatically Detect If a Form Is Being Edited in Access 2000

This article describes two techniques that you can use to automatically run code when a form's Edit mode changes. You can use these techniques when you want to have different controls available on a form when a record is being edited and when a record is not being edited.

NOTE: This article explains a technique demonstrated in the sample file, FrmSmp00.mdb. For information about how to obtain this sample file, please see the following article in the Microsoft Knowledge Base: Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.
When Access displays a pencil symbol in the record selector, the record is being edited, but it has not yet been saved. When 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.
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 as follows:

      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 dimmed.
8. Modify any field in the current record, and then press the TAB key. Note that the Undo Record button becomes available.
9. Click Undo on the Edit menu to undo your changes. Note that the Undo Record button becomes dimmed.

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.

For more information about the Dirty property, click Microsoft Access Help on the Help menu, type the Dirty property in the Office Assistant or the Answer Wizard, and then click Search to view the topic.


For more information about Timer event, click Microsoft Access Help on the Help menu, type Timer event in the Office Assistant or the Answer Wizard, and then click Search to view the topic.