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VB Forum / COM / July 2008429 ActiveX component can't create object when using late binding
Hi there, why would I receive the above error when I use CreateObject? The following code works: Dim obj as MyComObj Set obj = New MyComObj but if I use the following code it errors: Dim obj Set obj = CreateObject("MyComObj") Why are you using CreateObject? Is late-binding necessary? Is MyComObj the name displayed in the ObjectBrowser? This is one of those questions that requires more details, I think.  SignatureRichard Grier, MVP Hard & Software Author of Visual Basic Programmer's Guide to Serial Communications, Fourth Edition, ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March 2006. See www.hardandsoftware.net for details and contact information. > Why are you using CreateObject? Er, no particular reason. I am just trying to blow out the cobwebs and create a C++ COM library. (It's been a while!). This was just to test that I had created it correctly. >Is late-binding necessary? No. I just wanted to understand why it doesn't work. > Is MyComObj the name displayed in the ObjectBrowser?# No. That's something I made up for this post. I can see the object in the object browser. > Hi there, > why would I receive the above error when I use CreateObject? [quoted text clipped - 10 lines] > > Set obj = CreateObject("MyComObj") You've only provided half of the progid (the string you pass to CreateObject). Using MS Word as an example: Dim oWord As Object Set oWord = CreateObject("Word.Application") oWord.Visible = True oWord.Quit Set oWord = Nothing Note the string "Word.Application"...2 parts to it separated by a period. SignatureMike Microsoft Visual Basic MVP > You've only provided half of the progid (the string you pass to > CreateObject). As I stated in the previous post, that name was only for posting. I actually used the "library.interface" name as shown in the object browser. I was hoping that someone could tell me what was wrong with the COM object. ie: I thought that it had to be Dual and IDispatch to work VB e.t.c. > Hi there, > why would I receive the above error when I use CreateObject? [quoted text clipped - 10 lines] > > Set obj = CreateObject("MyComObj") While they are often spelled the same they are two totally different identifiers. "MyComObj" as used in: Dim obj As MyComObj Is an Interface ID as published with a Typelib. "MyComObj" when used with CreateObject is a ProgID or AppID as defined in the registry. If you examine the Registry you will see ProgID/AppIDs do nothing more than redirect to a registered type. While Library/Interface IDs are chiselled in stone by the component's published Interface, ProgIDs can be anything the development tool decides. C/C++ tools tend to use coclass::class by default, VB uses library::Interface. Note again, they are often the same, but not always. In fact you can go into the registry and create your own... As long as it resolves to an existing component it will work fine. Anyway, the latter is failing because you don't have a Registry entry for that ProgID, or the entry value is invalid. hth -ralph |
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