ACC: Macro on Subform Control Executed by Main Form (100150)

SYMPTOMS

If a macro is attached to the OnEnter or OnExit property of the first control in the tab order of a subform, the macro will run each time you move from one record to another in the main form.

In addition, a macro attached to the OnEnter property of the first control in the tab order of the subform will run when the main form is opened, and a macro attached to the OnExit property of the first control in the tab order of the subform will run when the main form is closed.

NOTE: This behavior is also true for Visual Basic for Applications code (or Access Basic code in Microsoft Access 2.0 or earlier) attached to the OnEnter or OnExit property.

CAUSE

To cause a macro to run only when you are actually moving in and out of the subform, use a test condition with a flag. A macro can set a flag on the main form to indicate whether the subform was entered by moving into the subform from the main form. The macro attached to the subform's OnEnter and OnExit properties can check this flag to see if you really did move into the subform and continue running if appropriate. The following steps demonstrate how to set up and test for this condition.

RESOLUTION

Create the following macro called Subform Flag:

      Macro Name     Action
      -----------------------
      Set            SetValue
      UnSet          SetValue

      Subform Flag Actions
      -----------------------
      SetValue
         Item: [Subform Flag]
         Expression: True
      SetValue
         Item: [Subform Flag]
         Expression: False

For a form named MyForm, add an unbound text box to the main form with the following properties:

      Form: MyForm
      Text Box: Subform Flag
         Name: Subform Flag (in version 1.x, ControlName: Subform Flag)
         Visible: No
         Default Value: False

Select the subform control on the main form and change the following properties:

      Form: MyForm Subform
      On Enter: Subform Flag.Set
      On Exit: Subform Flag.UnSet

Add the following macro action to the top of the macro that is attached to the OnEnter or OnExit property of the first control in the tab order of the subform. The macro will not perform any other actions if the subform flag is not set.
```
      Condition                       Action
      -----------------------------------------
      Parent![Subform Flag] = False   StopMacro
```

The macro attached to the OnEnter property of the first control in the subform will not run if you enter the control from the main form and the control is in the selected record on the subform (denoted by a triangle in the record selector). As a result, the macro will not run when you enter the subform by pressing TAB, or by clicking the first control in the selected record on the subform. However, the macro will run if you click this control on a different record in the subform.

MORE INFORMATION

Steps to Reproduce Behavior

Open the sample database Northwind.mdb (or NWIND.MDB in Microsoft Access versions 1.x and 2.0) and create the following macro called Test:

      MacroName     Action
      --------------------
      Test          MsgBox

      Test Actions
      --------------------
      MsgBox
         Message: Testing!

Open the Orders Subform form and change the OnEnter and OnExit properties of the PropertyID box ( or Property ID box in versions 1.x and 2.0) box to Test, as follows:
```
      Form: Orders Subform
      OnEnter: Test
      OnExit: Test
						
```
Save the Orders Subform form, open the Orders form, and move among the records. Note that the message "Testing!" appears twice for each record.