ACC2000: How to Dynamically Unlock a Control with a Message Box

To protect the data in a control on a form from accidentally being changed, you can use a message box to prompt for verification when you try to enter data into that control. Clicking Yes in the message box unlocks the control, and allows you to type.

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. The following example displays a message box to verify that the user wants to update the Description text box in the Categories form in Northwind.mdb.

CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.

1. Start Microsoft Access, and open the sample database Northwind.mdb.
2. Open the Categories form in Design view.
3. Click Code on the View menu, and type the following line in the Declarations section:

   Public fEditDescription As Boolean
   					

4. Set the OnCurrent property of the form to the following event procedure:

   Private Sub Form_Current()
   
      ' Lock the Description control for each record.
      Me!Description.Locked = True
      fEditDescription = False
   
   End Sub
   					

5. Open the property sheet of the Description text box, and change the Locked property to Yes.
6. Set the OnKeyDown property of the Description text box to the following event procedure:

   Private Sub Description_KeyDown(KeyCode As Integer, _
      Shift As Integer)
   
      ' If the field is not flagged for editing, prompt the user
      ' for confirmation about unlocking the control.
      If fEditDescription = False Then
         If MsgBox("Do you want to change Description?", _
               vbYesNo + vbQuestion + vbDefaultButton2, _
               "Confirmation") = vbYes Then
   
            ' If the response is Yes, unlock the field
            ' and flag it as being edited.
            Me!Description.Locked = False
            fEditDescription = True
         End If
      End If
   
   End Sub
   					

7. Switch to Form view and try to change the contents of the Description text box.
   
   Note that a message box appears and asks whether you want to change Description. If you click Yes, Description is unlocked and you can edit its contents for that particular record. If you click No, Description remains locked.

For more information about the MsgBox() Function, click Microsoft Access Help on the Help menu, type MsgBox Function example in the Office Assistant or the Answer Wizard, and then click Search to view the topics returned.