ACC2000: Undo Method Causes IPF When Used Outside Form's Class Module (235222)

SYMPTOMS

If you invoke the Undo method of a form outside the form module, such as in a global procedure, a global function, or from the Immediate window, you may receive an error similar to one of the following:

Dr. Watson for Microsoft Windows NT

An application error has occurred and an application error log is being generated. MSACCESS.exe Exception: access violation (0xc0000005), Address: 0x3005e7c4

On Microsoft Windows 95/98

MSACCESS caused an invalid page fault in module MSACCESS.EXE at 015f:3005e7c4.

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RESOLUTION

To resolve this problem, obtain Microsoft Office 2000 Service Release 1/1a (SR-1/SR-1a).

To obtain SR-1/SR-1a, click the article number below to view the article in the Microsoft Knowledge Base:

245025 OFF2000: How to Obtain and Install Microsoft Office 2000 Service Release 1/1a (SR-1/SR-1a)

To temporarily work around this problem do the following.

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.

Instead of invoking the Undo method from a public module, call Form.Undo from the code module of the form, as in the following example:

Open the sample database Northwind.mdb.

Create a new form with the following characteristics:

   Form: Test1
   -------------------------
   Caption: TestForm
   RecordSource: Categories

   Command button
   ------------------------
   Name: Button0
   Caption: My Button
   OnClick: Event Procedure

   Text box
   ---------------------------
   Name: CategoryName
   ControlSource: CategoryName

   Text box
   --------------------------
   Name: Description
   ControlSource: Description

In Design view, right-click the command button, and click Build Event on the menu that appears.
Click Code Builder, click OK, and type the following code in the resulting module:
```
Private Sub Command0_Click()
   Form.Undo
End Sub
					
```
View the form in Form view and make a change to the description of any record.
Click the command button.

Note that your change was undone and that no error occurs.

MORE INFORMATION

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.

Steps to Reproduce Behavior

Open the sample database Northwind.mdb.

Create the following new form. and then save it Test1:

   Form: Test1
   -------------------------
   Caption: TestForm
   RecordSource: Categories

   Text box
   ---------------------------
   Name: CategoryName
   ControlSource: CategoryName

   Text box
   --------------------------
   Name: Description
   ControlSource: Description

View the form in Form view. You do not have to make any changes to any record on the form.
Press CTRL+G to open the Immediate window.
With the form open, type the following in the Immediate window, and then press ENTER:
```
Forms("Test1").Undo
					
```

Note that you receive one of the errors described in the "Symptoms" section of this article.