I have 2 .net dll's which I expose to COM using REGASM. In order to simplify referencing within a COM client I would like to make these into one file.
I have tried converting both files to IDL and then copying the contents of the Library section of one into the other and then compiling back to .tlb with MIDL. This works fine for the TypeDefs within the second IDL however it seems to fail when it comes to the interfaces I copied in. OLE/COM viewer can see the interface definitions but when I try and use the TLB via COM it cant find the interfaces that I copied in.
I wanted to make sure before I spend too much time on this, that it is actually possible to meagre IDL's in this way.
Could you use ILMerge to first combine the .NET assemblies and then use REGASM on the resulting assembly?
ILMerge is a utility for merging
multiple .NET assemblies into a single
.NET assembly. It works on executables
and DLLs alike and comes with several
options for controlling the processing
and format of the output.
I don't see an obvious way this would fail. You said you merged the library sections but you didn't say you copy-pasted the interface declarations from the other .idl. That would be an obvious, but unlikely, explanation.
One failure mode is when the client app uses the type library to marshal interface pointers across apartment boundaries or out-of-process. That however requires registry keys in HKCR\Interfaces. .NET doesn't create them, you'd have to do that yourself. You'd know if you did, not much of an explanation either.
Ok so it turns out that the issues I was experiencing were not related to merging the idl's.
If you wish to merge to idl's you can do so by simply copying the content of a library section in one idl into another. Then run midl on the merged file to turn it into a tlb.
Related
How can one programmatically determine which type libraries (GUID and version) a given native, VB6-generated DLL/OCX depends on?
For background: The VB6 IDE chokes when opening a project where one of the referenced type libraries can't load one of its dependencies, but it's not so helpful as to say which dependency can't be met--or even which reference has the dependency that can't be met. This is a common occurrence out my company, so I'm trying to supplement the VB6 IDE's poor troubleshooting information.
Relevant details/attempts:
I do have the VB source code. That tells me the GUIDs and versions as of a particular revision in the repo, but when analyzing a DLL/OCX/TLB file I don't know which version of the repo (if any--could be from a branch or might never have been committed to a branch) a given DLL/OCX corresponds to.
I've tried using tlbinf32.dll, but it doesn't appear to be able to list imports.
I don't know much about PE, but I popped open one of the DLLs in a PE viewer and it only shows MSVBVM60.dll in the imports section. This appears to be a special quirk of VB6-produced type libraries: they link only to MSVBVM60 but have some sort of delay-loading mechanism for the rest of the dependencies.
Even most of the existing tools I've tried don't give the information--e.g., depends.exe only finds MSVBVM60.dll.
However: OLEView, a utility that used to ship with Visual Studio, somehow produces an IDL file, which includes the importlib directives. Given that VB doesn't use IDL files, it's clearly generating the information somehow. So it's possible--I just have no idea how.
Really, if OLEView didn't do it I'd have given it up by now as impossible. Any thoughts on how to accomplish this?
It turns out that I was conflating basic DLL functionality and COM. (Not all DLLs are COM DLLs.)
For basic DLLs, the Portable Executable format includes a section describing its imports. The Optional Header's directory 1 is about the DLL's imports. Its structure is given by IMAGE_IMPORT_DESCRIPTOR. This is a starting point for learning about that.
COM DLLs don't seem to have an equivalent as such, but you can discover which other COM components its public interface needs: for each exposed interface, list out the types of their properties and their method arguments, and then use the Registry to look up where those types come from. tlbinf32.dll provides some of the basic functionality for listing members, etc. Here's and intro to that.
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'm trying to create an D application which uses a (third party) COM .dll so I can scrape a text box of another application so I can sound an error when a certain string shows up.
However the third party doesn't provide .lib, .def or .h files that go with the dll (atleast with the free trial version). I can create the .lib file with the implib tool but I don't see any of the library's functions in the created .lib.
Their (visual c++) samples use the #import directive to link it in however that is of no use for me ...
On a side note how can I get the proper interfaces (in a .di with boilerplate that does the linking) of the dll automatically? I ask so the correctness of the linkage doesn't depend on my (likely to be incorrect) translation of the functions. They do have a webpage which gives all functions but the object model is a bit chaotic to say the least.
From what I know, COM libraries only expose a few functions, required to (un)register the library and to create objects.
You can however view the interfaces and functions in a COM .dll using the OLE/COM Object Viewer. It seems it might be able to output header files (.h). Afterwards, maybe you could use htod as a starting point to converting everything to D interfaces.
The DMD distribution seems to include a .COM sample (chello.d, dclient.d, dserver.d), and at first glance it doesn't look like it would require any LIBs explicitly.
Unfortunately, I've never actually used COM in D, so I can't advise any further. I hope this helps in some way.
While I have yet to actually do COM work myself, I am trying to revive Juno over on Github/he-the-great. Part of the project is tlbimpd which is what will output a D file from a DLL.
I've tested the examples and successfully run tlbimpd. Please do try things out for your use and submit any issues.
I'm trying to work with an existing home grown implementation of click-once. Currently we manually update the manifest for assemblies that we actually changed. I'm attempting to make it automatic based on a binary comparison of the existing assemblies and the newly built assemblies. Unfortunately, it seems that each time I run clean + build (automated build script) there are small differences to the assemblies, essentially invalidating the use of our click-once solution at all. I'm guessing that these differences are caused by some sort of guid generation or something along those lines. Is there anyway to prevent the differences in the assemblies?
And unfortunately, due to our branching/CI strategy I don't have the option of not cleaning because each release is from a new branch.
Otherwise, any suggestions on how I can compare two assemblies to see if any code has changed, without having access to the source code.
Thanks,
David
Typically, autobuild systems check the filesystem timestamps of the binary vs the source files (or object files vs source files, depending on the language). If the source is newer than the binary/object, a rebuild is triggered. This strategy may work better for you instead of actually diffing binaries/
I found BitDiffer a tool from www.BitWidgets.com that compares what has changed in an assembly. While this runs slower than a binary comparison, it removes the need to have MSBuild create an identical assembly.
Thanks,
David
Apologies if this is a duplicate, but I've not managed to find this question being asked directly.
The general opinion here (that's me and him across from me) is that they shouldn't, the reason being that DLLs can be shared; therefore the idea of having application-specific information in a DLL is nonsense. If the information is not application-specific, then constants can be used.
A further question is, assuming that DLLs do not have their own config file, whether DLLs should use the configuration files of the executable that loaded the DLL, or instead be passed the relevant data as part of some kind of constructor. Our opinion here is the latter, as it makes it more testable, the downside being that it will sometimes be necessary to pass a significant amount of data to the dll.
Opinions?
There's no reason why you can't have the best of both worlds in terms of "simple to configure with config files" and "testable". Have a static method which can create instances from the configuration file, but also provide a constructor for more control and testability. The static method would just grab the settings and call the constructor.
I believe it's possible to create settings classes for DLLs just like any other project, and then you just need to put the actual text into the application's config file instead of one for the DLL. Basically ignore the app.config generated for the library project, except to use as a template for the application's central one.
Alternatively, use something like Spring.NET to manage this sort of thing :)
Usually, I guess you should pass relevant information to the functions you're calling or set relevant properties in objects you're creating that are defined within the DLL. I guess that's why .NET does not really support config files for DLLs (you can create them, but they'll not be used when running).
I have one scenario, where DLLs are reading a config file, but that is very special: The .NET DLL exports objects as COM objects for use by Microsoft Navision. It communicates with a factoring bank using an XML-RPC interface.
While the DLL is installed on every user's machine, the configuration for the interface is common to all users, so I have a configuration placed on a network drive that's mapped on every PC and the configuration (URL, credentials, etc.) is read from that common file.
Whether that's good practice is up to the reader, but in that scenario having a common config file just made sense...