Source Code for Collection Example 3
Form A
Function Options(*DIRECT)
Begin_Com Role(*EXTENDS #PRIM_FORM) Caption('Form A') Clientheight(108) Clientwidth(336) Height(135) Layoutmanager(#GDLM_1) Left(286) Top(124) Width(344)
* Using a Keyed Collection (PRIM_KCOL) to handle a multi-form application.
* Define the keyed collection to be used to store the child forms.
* The collection is named #FormBs and it collects #FormBs.
* It is keyed by #Std_Num ie: a packed (7,0) number.
Define_Com Class(#Prim_Kcol<#FormB #Std_Num>) Name(#FormBs)
* Define the form.
* CreateFormBtn will create an instance of FormB
* MoveRightBtn will move all the child FormBs to the right
* MoveLeftBtn will move all the child FormBs to the left
Define_Com Class(#PRIM_PHBN) Name(#CreateFormBtn) Caption('Create a Form B') Displayposition(1) Left(30) Parent(#COM_OWNER) Tabposition(1) Top(29) Width(109)
Define_Com Class(#PRIM_PHBN) Name(#MoveRightBtn) Caption('Move all Form Bs Right') Displayposition(2) Left(139) Parent(#COM_OWNER) Tabposition(2) Top(29) Width(166)
Define_Com Class(#PRIM_PHBN) Name(#MoveLeftBtn) Caption('Move all Form Bs Left') Displayposition(3) Left(139) Parent(#COM_OWNER) Tabposition(3) Top(54) Width(166)
* Grid layout manager to position the buttons
Define_Com Class(#PRIM_GDLM) Name(#GDLM_1)
Define_Com Class(#PRIM_GDLI) Name(#GDLI_1) Manage(#CreateFormBtn) Parent(#GDLM_1)
Define_Com Class(#PRIM_GDLI) Name(#GDLI_2) Left(2) Manage(#MoveRightBtn) Parent(#GDLM_1)
Define_Com Class(#PRIM_GDLI) Name(#GDLI_4) Left(2) Manage(#MoveLeftBtn) Parent(#GDLM_1) Top(2)
* Definition of child form (FormB)
Define_Com Class(#FORMB) Name(#FORMB) Componentversion(1)
* Fields used to position the child forms (FormB)
Define Field(#NEW_TOP) Reffld(#STD_NUM)
Define Field(#NEW_LEFT) Reffld(#STD_NUM)
Evtroutine Handling(#CreateFormBtn.Click)
* Use the keyed collection property ItemCount to get the next slot in the collection
Change Field(#LISTCOUNT) To('#FormBs.ItemCount + 1')
* Show the form. When the form is shown, it is created and added to the collection
Invoke Method(#FormBs<#listcount>.showform)
* Adjust the form's position from the left and top
Change Field(#NEW_LEFT) To('#FORMBS<#listcount>.Left + (#listcount * 30)')
Change Field(#NEW_TOP) To('#FORMBS<#listcount>.top + (#listcount * 30)')
Set Com(#formBs<#listcount>) Left(#NEW_LEFT) Top(#NEW_TOP)
Endroutine
Evtroutine Handling(#MoveRightBtn.Click)
* Invoke the MoveRight method in FormB to move all forms in the collection to the right
Invoke Method(#formBs<>.MoveRight)
Endroutine
Evtroutine Handling(#MoveLeftBtn.Click)
* Use a For/EndFor loop to iterate through all the forms in the collection and to move them to the left
For Each(#Current) In(#FormBs)
Change Field(#NEW_LEFT) To('#Current.Left - 5')
Set Com(#Current) Left(#New_Left)
Endfor
Endroutine
End_Com
Form B
Function Options(*DIRECT)
Begin_Com Role(*EXTENDS #PRIM_FORM) Caption('Form B') Clientheight(103) Clientwidth(180) Formstyle(StayOnTopChild) Height(130) Layoutmanager(#ATLM_1) Left(591) Top(136) Width(188)
* Define the child FormB used by FormA
* Define a label
Define_Com Class(#PRIM_LABL) Name(#LABL_1) Alignment(Center) Caption('Form B ') Displayposition(1) Height(103) Left(0) Parent(#COM_OWNER) Tabposition(1) Tabstop(False) Top(0) Verticalalignment(Center) Width(180)
* Center the label on the form using an attachment layout
Define_Com Class(#PRIM_ATLM) Name(#ATLM_1)
Define_Com Class(#PRIM_ATLI) Name(#ATLI_1) Attachment(Center) Manage(#LABL_1) Parent(#ATLM_1)
* Define a field to position the form
Define Field(#NEW_RIGHT) Reffld(#STD_NUM)
* Method to move the form to the right by incrementing the value of its Left property
Mthroutine Name(MoveRight) Help('This method moves the form to the right.')
Change Field(#NEW_RIGHT) To('#COM_OWNER.LEFT + 5')
Set Com(#com_owner) Left(#NEW_RIGHT)
Endroutine
End_Com
When you create a new form and specify an ancestor for it, the inheriting form will look and behave exactly like its ancestor form.