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.
Related
When I register a .NET assembly enabled for COM interop using the REGASM tool, the tool creates a separate registry key for each component version. For example, I get:
HKEY_CLASSES_ROOT\CLSID\{myCLSID}\InprocServer32\1.0.0.0
HKEY_CLASSES_ROOT\CLSID\{myCLSID}\InprocServer32\1.1.0.0
etc.
Each of these registry contains roughly the same structure values as it is under HKEY_CLASSES_ROOT\CLSID{}\InprocServer32, except that the entries point to different locations, depending on the component version. The HKEY_CLASSES_ROOT\CLSID{myCLSID}\InprocServer32 apparently contains the latest registered version, and that's what COM consumers will normally use, of course, and they ignore the rest.
This structure apparently allows different versions of the component coexist on the same computer (I know it is against the originally specified COM rules). I would like to use it, but I could not find any documentation about it anywhere in the Microsoft documentation or Googling for it. Does anybody know? I am looking for something like CoCreateInstance/CoCreateInstanceEx with the version specifier.
Thanks
I'm trying to interact with a .dll which will allow me to receive information from a variety of devices (Eye Gaze to be specific). The .dll is called ETUDriver and can be found at http://www.sis.uta.fi/~csolsp/projects.php however it does not come with an accompanying .h file.
I am struggling to actually load, interact and invoke functions from the .dll. A manual is supplied but it is of no help whatsoever with regards to actually setting up the code to start it off. There are three accompanying example apps (with source code) but only two of these work and one of which is in C# so is not helpful. The one that works however loads up the .dll via MFC and this is not a viable option with my code (which is intended to be used with many other projects and as such can't enforce MFC or any other libraries that are not as standard to projects).
Essentially, within the .dll is a series of classes which I need to create within my code and invoke the relevant functions of that class.
I've tried to use HRESULT hr = CoInitialize(NULL);
hr = CoCreateInstance(__uuidof(ETUDSink), NULL, CLSCTX_INPROC, __uuidof(IETUDSink), (LPVOID*)&pETUDSink);
if(pETUDSink)
{
pETUDSink->Start();
} however it always returns an error saying that the class is not registered. I can't use MFC to call the relevant .rgs file and am completely stuck on how to get this to work otherwise.
Is there a given format to doing this that I am unaware of and has anyone had experience in using the ETUDriver (or is able to get it working in C++ without use of MFC)?
Thank you for any help you can provide on this subject :)
I am not familiar with the specific DLL in question, but it sounds like you did not register the DLL on the target machine. You can do this by running regsvr32.exe or by calling the DLL's exported DllRegisterServer function or by using side-by-side assemblies. You need to do register the DLL on each machine that needs to leverage the COM functionality within it, so when you distribute your application, make sure that your installer registers the DLL if you go the regsvr32.exe route.
You can use the #import directive in Microsoft Visual C++ to load the information contained within the DLL without using a header file or rewriting it yourself based on documentation.
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
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.
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