VB6 Error - Cannot load .ocx File - com

I have been trying to load a OCX file into one of my VB6 projects for most of the day today. I've tried checking the COM registration in the registry the best that I know how, and have attempted several times using REGSVR32 on the file to no avail. All I keep getting from VB6 when I try to load the component (Under Project --> Components) is 'FilePath\FileName.ocx' could not be loaded. Has anyone else seen this before, and if so, any ideas how to fix it?

Just a couple of tips to help isolate the problem....
Look at the control with OleView
Examine the name: if it is one of the reserved words such as 'Menu', vb6 will fail to load it. (Although vb6 will happily let you create (and use) one with a bad name until it is saved and reloaded)
Examine the interface: does it describe the functionality? You may have a damaged or unlicensed ocx.
Attempt to load it with the ActiveX Control Test Container...
If you can, the problem is with VB6 and not the ocx.

This it may be a dependency issue -- some other component needed by the OCX is not present. Dependency Walker will find any static dependencies.

We fixed similar error recently. In our case the error was in the Visual Basic project (.vbp) file. Project file had been edited outside standardized build machine and contained references to OCX components - including workstation specific paths & versions of the components.
You can either edit the the project file in text editor or get a working version from version control.

Un-registering and registering again worked for me too.
Please note that you need to register this component using this syntax:
regsvr32 /i:design olch2x8.ocx

When you say you have used "REGSVR32 on the file to no avail" do you mean that you get a file name succeeded message, or an error message? If registering the file succeeds CMB is likely right about the ocx being unlicensed.

Licensing aside, there are a couple of other trip points with vb6. Especially if the OCX was developed in VB6.
If so, the 'officially' system registered version may conflict with the specific ocx you're using. In other words, both of them might have the same proper name (or classid) but the one you're attempting to use may not implement all the functionality described in the system registered one (i.e. you have a less evolved version). This arises when the author desires to maintain binary compatibility while enhancing the functionality of a control. As long as the public interfaces remain compatible, vb will not recalculate the classid.
You can fix this by forcibly unregistering the specific control (actually unregister all instances of the control). (regsvr32 /u control.ocx ) Then re-register the one you intend to use. Be certain that no running instance of VB6 exists when you do this or the results might not work. (Check your task list)
Hope that helps...

The control may be reliant on another DLL or OCX that may be missing or not registered and this could manifest itself as VB reporting that the control you're trying to use is missing. However, I'm not sure how you would identify the dependencies. As far as I know, dependency walker identifies static dependencies; I'm not sure if it can identify COM dependencies.

Un register the Ocx
re register the ocx
then loaded the project again in VB6, it worked for me.
Thanks everyone

Related

VB6 reference confusion

I am a .NET Developer. I have a good understanding of how references work in .NET i.e. if you want to use AssemblyA.ClassA.MethodA in AssemblyB.classB.MethodB then you add a reference in Assembly A to Assembly B.
I am looking at a VB6 app and I get an error when I open it i.e. Errors during load. Refer to frmMain.log. I open frmMain.log and it says: "2142: Class MSComDlg.CommonDialog of control CommonDialog1 was not a loaded control class.". I have used WinMerge to compare the source code in the faulty project to a previous version of the project (which does not have the problem). The only difference is that the faulty project contains the following line in the client.vdp file:
Reference=*\G{08DBEFD7-6A19-4DCE-A533-5BDBB93683C8}#1.2#0#..\..\..\..\..\Windows\SysWOW64\Comdlg32.oca#Microsoft Common Dialog Control 6.0 (SP3)
Removing this line seems to resolve the problem. Why does this resolve the problem?
I have used Winmerge to compare yesterdays revision of the project (which does not have the problem) to todays revision of the project (which does have the problem). The only difference is the reference in the original post in the VBP file.
I would assume that someone installed the development version of this control on a different machine and then set a reference to it. When you try to open the project on your machine the reference fails. Or the control was uninstalled. It seems that the project was not using the reference and that it can be safely removed as it will still compile without the reference.
However, I have seen vb6 actually remove non-licensed controls from the form in question in this situation. So it may be that you can now compile because the form is missing a component that was there previously. Have you checked that frmMain has not changed, both the .frm and .frx files?

Will having two different versions of a DLL cause issues?

I have a vb6 program that needs to use MSOLAP80.dll to display its pivot tables properly. But because MSOLAP90.dll has some compatibility issues with this I cannot use MSOLAP90.dll and still have the pivot tables display.
I have registered MSOLAP90.dll and then registered MSOLAP80.dll again and everything seems to be fine. I however don't know if both are actually registered or if MSOLAP80.dll is the only one registered, because I have no reference point as to what is new in MSOLAP90.dll. Is it possible that both are registered and the program is just using MSOLAP80.dll and if there are programs that need MSOLAP90.dll then it will know to use that one?
I guess I am just confused about how registering DLL's work and if it is possible to have both of these registered at the same time. Can somebody help with an explanation?
If you want to know for sure which one is registered, you can:
Look at the References dialogue for a type library which matches your DLLs' paths.
Open up RegEdit, and search for MSOLAP80.DLL or MSOLAP90.DLL (uncheck "Match whole string only").
If you find references for both DLLs, then you are safe because you can bind to a specific version. If you find a reference to the wrong DLL, then unregister the wrong one, and register the right one.
COM originall only allowed one version of a set of CLSIDs (which uniquely identify classes), IIDs (which uniquely identify classes' interfaces) at any one time. It is possible to have more than one reference to a LIBID (which identifies a type library - a resource embedded in the DLLL) but they have to have different versions.
From Windows XP onwards, it became possible to do side by side DLL access in which an executable can access a specific version of a DLL, overriding the value in the registry. You need to embed or have a .manifest file in the same folder as the EXE file.
Unfortunately, the documentation for this seems to have disappeared from MSDN, and is only referred to by a couple of Knowledge Base articles:
http://support.microsoft.com/kb/828629
http://support.microsoft.com/kb/843524

VB.Net embedded Flash Object creates problems

Ì have had this problem in a number of projects and I have almost given up. I am sure there is a solution though. When I insert a Flash object in a VB.Net Windows Forms application, it works fine for a little while and then I see this error in the Design Screen. I am using Visual Studio 2010
Could not load file or assembly 'Interop.ShockwaveFlashObjects, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
I have read several descriptions of why this happens, and apparently it has something to do with strong naming (or lack thereof), but have not found a solution yet. I used Add Reference->COM->Shockwave Flash (C:\Windows\SysWOW64\Macromed\Flash\Flash32_11_2_202_235.ocx) If I ignore the error it appears to work fine, but I don't want my users to have a problem.
I know I can use a browser control and play the Flash in that, but for reasons I won't get into, I have to use a Flash control. Any ideas would help.
Okay. I can't promise this to work for you, but it worked for me.
First, you have to locate a file on your computer titled AxImp.exe. You have to run it from the command prompt. This file is located (for me at least) here:
C:\Program Files\Microsoft SDKs\Windows\v7.0\Bin\x64
Once you do find and run it, you have to point it to the correct Flash.ocx file you're using, like so:
AxImp.exe <path>\Flash.ocx
Once you've done that you should end up with 2 DLL files in the same directory as the .ocx file. One called AxShockwaveFlashObjects.dll and another called ShockwaveFlashObjects.dll.
You don't care about ShockwaveFlashObjects.dll, just AxShockwaveFlashObjects.dll.
Grab that file and the Flash*.ocx file and paste them into the project directory.
Then include them into your references. This should open up two new references, AxShockwaveObjects and ShockwaveObjects.
Make sure you're Using both of them.
After this, you have to register the Flash*.ocx using RegSvr32 from your command prompt (make sure to run CMD in admin mode). That is done like so:
C:\RegSvr32 <path>\Flash.ocx
This worked for me. I was having the exact same problem (which is what led me here). It could be a half backed hack workaround but for now, that's how it worked for me.
Let me know if it works for you or not.
Hope it goes well for you.
I know this is an old post but I had this issue yesterday and the solution, at least in my case, was very simple. All I had to do was to change the Platform and Platform Target to x86 (Build tab of project property).

COM OCX registration - 2 DLL's with same name

I have a native app that has an .OCX file that needs to be registered for it to be used in a .NET application.
Now currently there's different versions of this .OCX on the machine. Can someone please explain how this can affect the registration of this new (updated) .OCX file registration?
And how does my .NET app know which object to create from which .OCX file?
COM servers are required to change their CLSID guids if their interfaces are no longer compatible. So if your supplier did it right, you should be able to register both of them and get the right one when you use the right reference in your project.
Like any rule, this one got violated often and is presumably the reason you started this question in the first place. The back-up plan is to use registry-free COM, you write a manifest and add it to your program so it always uses the local copy of the COM server DLL instead of the one that was registered. Find out how to do this by googling "regfree COM", I see many relevant and useful hits at the top.
I believe COM class registrations include the entire path to the "server" providing the COM component. If the two versions of the .OCX have different class GUIDs, then there should be no issues.

ActiveX component can't create an object

I am getting error,
ActiveX component can't create object.
Actually I have VB6 DLLs where business logic resides and I am calling that DLL function in my VB.NET application, all DLLs are dependent on other DLLs. I am getting the error from one of the DLLs
Any ideas?
Usually that error points to a COM dll that is not registered. You need to look at the chain of calls and find out which COM components you need and make sure they are available. Process Monitor (from sysinternals) may help you find it when it reads from the registry and can't find it.
Four common causes are:
1. You do not have a required TLB or ActiveX DLL/OCX file
2. A TLB or ActiveX DLL/OCX needed by the project is present but not registered on your system
3. The VB runtimes are an earlier version than the one you need to run the project
4. A required TLB or ActiveX DLL/OCX file is corrupt
Do you have access to the troublesome DLL source code?
Also check permissions. The user account that the vb.net application is running under will need permissions to be able to create the vb6 dll
Process Monitor will definately help find the missing DLL, but frequently the task can be achieved more quickly with Dependency Walker.