DOCUMENT:Q190634  07-AUG-1998  [vbwin]
TITLE   :PRB: Activate Event Is Not Triggered with Child Form of MDI Form
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Visual Basic Professional and Enterprise Editions for
   Windows, versions 5.0, 6.0
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SYMPTOMS
========

The Activate event for an MDIChild form is only triggered the first time
the form is shown. For example, when an MDIChild form is displayed using
the Show Method, then hidden using the Hide method, and then shown again
using the Show method, the Activate event is triggered only the first time
the form is shown.

CAUSE
=====

The Activate and Deactivate events occur for MDI child forms only when the
focus changes from one child form to another. In an MDIForm object with two
child forms, the child forms receive these events when the focus moves
between them. However, when the focus changes between a child form and a
non-MDI child form, the parent MDIForm receives the Activate and Deactivate
events.

RESOLUTION
==========

To work around this behavior, create a custom method in Form1 to handle
showing the form. In the custom method, place code to show the form as well
as code you would have placed in the Activate event. To display the child
form, call the custom method instead of using the form's Show method. An
example custom method to show a child form and simulate an Activate event
would be:

   Public Sub MyShow()
      Form1.Show
      MsgBox "MyShow - simulation of Activate event"
   End Sub

The call to invoke this custom method would be:

   Form1.MyShow  'Call the custom method created in Form1

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Create a new standard EXE project. Form1 is created by default.

2. Choose Project, Add MDI Form, to add an MDI form.

3. Choose Project, Project1 Properties, and then set MDIForm1 to be
   Project1's Startup Object.

4. Select Form1 and change the Name and Caption properties of Form1 to
   frmChild. Set frmChild's MDIChild property to True.

5. In the Activate event of frmChild, place the following code:

      MsgBox "MDIChild Activate Event"

6. Place a CommandButton on frmChild. In the Click event for the
   CommandButton, place the following code:

      Me.Hide

7. Select MDIForm1 (the parent form). Open the Visual Basic Menu Editor to
   place a menu item on the MDI form. Set the Caption of the menu item to
   "Show MDIChild." Set the Name of the menu item to "mnuShow." In the
   Click event for the mnuShow menu item, place the following code:

       rmChild.Show

8. Press the F5 key to run the application. Click the Show MDIChild menu
   item. The message box appears as the child form is displayed. Click the
   CommandButton on frmChild to hide the child. Click the Show MDIChild
   menu item again. The message box does not appear, indicating that the
   MDIchild's Activate event did not fire.

9. Select frmChild. Open the form's code window and place the following
   workaround code:

      Public Sub MyShow()
         Me.Show
         MsgBox "MyShow acting as Activate event"
      End Sub

10. Select MDIForm1. In the Click event for the mnuShow menu item, replace
    the previous code with:

      frmChild.MyShow

11. Press the F5 key to run the application. Click the Show MDIChild menu
   item. The message box appears as the child form is displayed. Click the
   CommandButton on frmChild to hide the child. Click the Show MDIChild
   menu item again. The message box appears again.

REFERENCES
==========

For documentation on this behavior, search for "Activate event" in Visual
Basic Online Help Index. Select "Activate,Deactivate Events."

Additional query words: kbMDI kbVBp600 kbVBp500 kbdse kbDSupport kbVBp
======================================================================
Platform          : WINDOWS
Issue type        : kbprb

=============================================================================

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