使用Z顺序和位置来组织MS Access中的打开表单

Question

For MS Access 2010, I need a way to flexibly maintain the position and Z-order when a dozen forms are open. There can be multiple instances of the Parent form, and each one can lead to multiple instances of the Child form (some background here ).

I want the user to be able to choose which form is top-most -- which means I don't want any forms set as Popup . Also, I want the Z-Order essentially preserved when a new Child opens. As the Child opens, the Parent loses the focus; at that point I'd like the Parent to drop back to its former position in the Z-order. I could add requirements along this line, but you get the idea ... I imagined a default behavior might do what I want, but if I have to assign Z-order locations from an array or something like that, I could accept that.

I also want to control the on-screen position of the Child forms (I mean only when they are first opened; they can be repositioned). If they open with the same X,Y coordinates, they'll appear stacked on top of each other and the user will have to reposition the top instance in order to see the others. That is inconvenient and, more important I think, disorienting.

So far I'm not able to have it all. I can get a nice cascade result by specifying X,Y positions, but it stops working when I use the flags to poke at the Z-order.

I've been using the API...

Declare Sub SetWindowPos Lib "user32" ( _
                ByVal Hwnd&, _
                ByVal hWndInsertAfter&, _
                ByVal X&, ByVal Y&, ByVal cX&, _
                ByVal cY&, ByVal wFlags&)

Global Const HWND_TOP = 0
Global Const HWND_TOPMOST = -1

SetWindowPos Hwnd, HWND_TOP, lngPosX, lngPosX, 0, 0, SWP_NOSIZE

I have different results when I try options for hWndInsertAfter& and wFlags& . Also when I set forms as Popup (results are better, but as mentioned, I want the user to bring any form to the top; therefore no Popup ).

(Hmm... I bet Popup (and 'Modal`) are precisely what bring the API into best usage, because while a "must-answer" dialog is showing, control basically reverts to Windows. Confirm?)

My biggest frustration is that documentation for the API seems fragmentary and incoherent. And I wonder, am I stuck with that API? Is there something else I can use? I'd love a VBA solution apart from the API, but I guess this is what the API is for. Still, is there a method I'm missing?

I can post my variant attempts in more detail, but I feel I've been shooting in the dark, so I will wait on your feedback.

Update

I tried Reading The Manual . I tried twiddling with "form ownership" and NO/TOPMOST . For the Child form, I still have to choose between:

1. Being able to set the position upon opening
2. Being able to bring the Parent form back "on top" of the Child

Answer 1

Sorry for the late answer! I bumped into this while searching for a related issue.

One way to manage Z-order 'Access-only' is to use Form.SetFocus. The general solution outline:

1. Keep an array or collection of your form names and their Z-orders
2. When Z-order changes:
3. Resort your list to reflect the new Z-order
4. Turn screen updating off: Application.Echo False
5. Iterate through your list of forms in reverse Z-order. Use Form.SetFocus for each form. This will put the highest form on top.
6. Turn screen updating back on: Application.Echo True

This should work as long as all of your forms are non-modal.

If you need modal forms, be aware that they are by default on top, and you can only have one modal form open at a time. You can still use the above logic, just be sure to set Form.Modal = False for every form not on the top.

This is the 'how' answer, but I can't offer advice as to whether this is a sound approach for your application.

Answer 2

I believe the solution doesn't exist, or isn't worth pursuing because it would lean on Windows API libraries that may not be available in a few years. (This pessimism is not based on specific insights; but in general I see big pressures on the Windows user interface, so it's easy to imagine things shifting.)

I see some other hazards. Users will open numerous windows; resources will fail at some point, and probably before then they'll have lost any advantages from a human analytical point of view. Nonetheless they'll continue past the point of diminishing returns. Also I can expect to find a few pitfalls that gobble development time and lead in the end to complaints no matter how much time I spend mitigating them. Think "multi-user" and you'll know what I mean.

Instead, I need to re-think the approach. The application offers complicated and sometimes volumnous information. There's a way to do it. Not this way.

I might delete this OP, but it's gotten three up-votes, so I'll wait and see what you think. I can always punt to community wiki.