The title says it all - this is a simple Collection-Wrapper which can act as a compatible
Replacement for the VBA.Collection - the fast Hash-Access of the VBA.Collection is used further -
but all the disadvantages with indexed access are avoided for the most typical use-cases.
At this occasion there were also some other enhancements made as:
- an Exists Method to check for Keys
- a RemoveAll-method
- can hand out Value- and Key-Arrays in appropriate Variant- or String-Arrays (with userdefinable LBound)
- in addition to the compatible Item-Method we have ItemByIndex and KeyByIndex too
- The unnerving behaviour to not allow Add(..., BeforeIndex) with an Index at constantly 1 (in case of Count=0) is gone
It should be also possible, to implement the Item-property also in Write-Direction (with Property Let/Set),
but I leave that for interested colleagues to explore - currently the internally used Collection-Instance-Types,
which were pointed out to me in this thread for the first time (structs posted by jbarnett74 - then refined with a few more
explanations by Bonnie West) - these Structures are currently only used within this wrapper in "safe-read-only-fashion".
Those who try themselves at implementing Write-Access for the Values over the Item-Property,
should test this accordingly (back and forward), because these Structs contain quite a few
"still unknown members", which partly are used for the Hashing-functionality of the VB-Collection,
but some of them could also store additional information, which is related to the Value-member
of the Element-Struct - so changing the Value-Member is alluringly simple - since it seems easily
accessible also for the Write-Direction - but one doesn't know yet, if changing its Value requires
also changes in a few so far unknown members (which the Add-Method of the VB-Collection might
automatically ensure under the covers).
So, as the implementation comes currently - it is "playing things safe" - no real risk in using it, especially
when you compile it into a dedicated ActiveX-Dll-Binary, to give the Class more IDE-safety with regards
to cleanup, even when the Stop-Button was pressed in the IDE (it needs to run over its Class_Terminate-
Event to clear things up properly).
Ok, so here is the Implementation- and Demo-Code (with a small performance-test):
CollectionEx.zip
And here the appropriate ScreenShot:
Image may be NSFW.
Clik here to view.
An additional advice for those who plan to compile it into an ActiveX-Dll-Binary,
all extended native Compiler-Options are allowed *aside* from the "Aliasing-Option"
(which should remain unchecked in this case of SafeArray-Pointer-usage).
Olaf
Replacement for the VBA.Collection - the fast Hash-Access of the VBA.Collection is used further -
but all the disadvantages with indexed access are avoided for the most typical use-cases.
At this occasion there were also some other enhancements made as:
- an Exists Method to check for Keys
- a RemoveAll-method
- can hand out Value- and Key-Arrays in appropriate Variant- or String-Arrays (with userdefinable LBound)
- in addition to the compatible Item-Method we have ItemByIndex and KeyByIndex too
- The unnerving behaviour to not allow Add(..., BeforeIndex) with an Index at constantly 1 (in case of Count=0) is gone
It should be also possible, to implement the Item-property also in Write-Direction (with Property Let/Set),
but I leave that for interested colleagues to explore - currently the internally used Collection-Instance-Types,
which were pointed out to me in this thread for the first time (structs posted by jbarnett74 - then refined with a few more
explanations by Bonnie West) - these Structures are currently only used within this wrapper in "safe-read-only-fashion".
Those who try themselves at implementing Write-Access for the Values over the Item-Property,
should test this accordingly (back and forward), because these Structs contain quite a few
"still unknown members", which partly are used for the Hashing-functionality of the VB-Collection,
but some of them could also store additional information, which is related to the Value-member
of the Element-Struct - so changing the Value-Member is alluringly simple - since it seems easily
accessible also for the Write-Direction - but one doesn't know yet, if changing its Value requires
also changes in a few so far unknown members (which the Add-Method of the VB-Collection might
automatically ensure under the covers).
So, as the implementation comes currently - it is "playing things safe" - no real risk in using it, especially
when you compile it into a dedicated ActiveX-Dll-Binary, to give the Class more IDE-safety with regards
to cleanup, even when the Stop-Button was pressed in the IDE (it needs to run over its Class_Terminate-
Event to clear things up properly).
Ok, so here is the Implementation- and Demo-Code (with a small performance-test):
CollectionEx.zip
And here the appropriate ScreenShot:
Image may be NSFW.
Clik here to view.
An additional advice for those who plan to compile it into an ActiveX-Dll-Binary,
all extended native Compiler-Options are allowed *aside* from the "Aliasing-Option"
(which should remain unchecked in this case of SafeArray-Pointer-usage).
Olaf