Things can get confusing if you multi-instance the same form. Here are a few things I've learned about working with _Screen.forms()

If, while traversing the collection, you close a form, this will require that you restart the process of traversing the collection. That is, changing the members of the collection while traversing the collection (such as within a FOR EACH loop) will cause some items in the collection to potentially be missed unless the loop is restarted.

If you need to keep track of a specific form (or window) -- again, particularly useful if you multi-instance forms -- it is helpful to give each form a unique name using a common root within the form's init. For example, if you have a form called CUSTOMER, then I've found it helpful to instantiate it with something like:

Thisform.Name="CUSTOMER_12345"

Downstream, if an event on some other form occurs such that you need to know if customer 12345's form already exists, you can do something like:

cCustomerWinName="CUSTOMER_" + cThisCustID
If Wexist(cCustomerWinName)
  Show Window (cCustomerWinName) top
  Activate Window (cCustomerWinName) 
Else
  Do Form FrmCustomer with cThisCustID
endif

You can search for a specific form and get it's object reference with a FOR EACH loop.

cCustomerWinName="CUSTOMER_" + cThisCustID
For each oCustFrm in _Screen.Forms
  If oCustFrm.name == cCustomerWinName
     return oCustFrm
     ....

and then you can use the form reference to access any items on/in the form (which itself is a container/collection data structure).


>Hi, all! Please answer which function can determinate does object (in my
sample form) exists or not. Thank you. Andrew