I have to use third party, unmanaged COM dll into my .NET application. I need to modify this assembly to produce a custom RCW. In order to Edit Interop Assembly I need the type library of the particular assembly. Can any one explain me that how to How to generate type library from unmanaged COM dll?
There is no option in regsvr32 to generate type library.
Thank you,
Best Regards,
Robo.
You need the OLE-COM Object Viewer, available as part of whatever is the latest Windows SDK. Then you can go to File->View Type Lib and save the IDL to a text file. Then you can use MIDL (also part of the Windows SDK) to regenerate a TLB and header file. Something like this should do for basic cases:
midl /out c:\temp /header MyHeader.h MyIDLFile.idl
If all you're trying to do is create an Interop Assembly from a native dll (and the native DLL embeds the TLB as a resource), you can just call tlbimp directly on the dll:
tlbimp Foo.dll /out:Interop.Foo.dll
Which will generate Interop.Foo.dll. You can then use ildasm to modify the IL:
ildasm Interop.Foo.dll /out=Foo.il
If all you have is that COM DLL, you can't generate a type library. A type library describes the COM interfaces implemented. But an unmanaged COM DLL merely needs to expose DllGetClassObject. This only gets you an IClassFactory, which lets you create new objects if you knwo the correct type up front.
If the typelib is embedded in the DLL Resources and the TLB file itself is what is required then 3rd party software can extract it (though, as others have pointed out, this may not be the most desirable option).
E.g. using Resource Hacker:
Open the DLL file.
Navigate to the TYPELIB\1\1033 (or whatever) node in the tree view.
From the menu, choose Action -> Save Resource as binary file...
Chose a file name and give it the .TLB extension.
You can now reference that .TLB file and build without requiring the original DLL, e.g.
#import "test.tlb" named_guids
Visual Studio IDE can directly extract binary resources from non-managed .exe and .dll files.
If the type library is saved as a binary resource in a non-managed COM DLL (e.g. one built using VS native C++ compiler), you can extract it as follows:
Open the .dll file in the VS resource editor (the default editor when opening executables).
Navigate to the type library resource ("TYPELIB", then 1) within the resource tree.
Right-click on the type library resource and select export. That brings up a "Save File As" dialog box.
In the "Save File As" box, change the filename from the default (typically, bin1.bin) to something like MyLibrary.tlb and click Ok.
Confirm by opening the exported .tlb file with OleView.exe (results should look identical to those you see by opening the .dll with the OleView.exe).
To extract type libraries from managed DLLs (e.g., the ones built using C#), VS includes the tool Tlbexp.exe (run it from the VS command prompt):
https://msdn.microsoft.com/en-us/library/hfzzah2c(v=vs.110).aspx
Related
I'm using a third party component in my application that is distributed either as a COM component, or can be referenced using a .manifest file. Either way it is loaded using CoCreateInstance(). The files needed for the third party component reside in a subfolder. The component developer told me to include a .manifest file in the Visual Studio 2010 settings (in the "Manifest" section) of the executable, and loading the component works without problems.
Now I'm using the third party component from a DLL only, to encapsulate the features used from the third party component. I'm loading the DLL dynamically, using LoadLibrary(). Using the component still works, I can use the component from within the DLL that is loaded by the EXE that has the manifest file referenced.
To further separate the EXE from the third pary component, I'd like to move the manifest to the DLL, too, where is the only place the component is used. In this way every new EXE I'd like to write can use the DLL and indirectly use the features. For now, I have to add the mainfest to every new EXE, but I don't want to do that.
Is there a way to move the manifest used by the EXE to a DLL?
You can put the manifest in the DLL, but it may not be activated automatically. You may need to do that manually using the activation context API. I think a lot depends on what the manifest is being used for. I suspect you are trying to use registration free COM, but that's only a guess.
Anyway, these links may well be useful to you:
RT_MANIFEST resource, and ISOLATION_AWARE_ENABLED (Junfeng Zhang)
Isolating Components (MSDN)
I do not have much experience working with COM and was wondering if anyone knew the minimum amount of information I have to provide to #import a dll into a cpp file (which will be used to make a dll). According to MDSN (http://msdn.microsoft.com/en-us/library/8etzzkb6(v=vs.80).aspx) I need to include a type library resource such as an .ocx file. Is this the case even for a Microsoft shared dll (e.g. mso.dll)? In addition, what are the other type library resources can I use?
From what I have gathered so far, I just need to provide enough information to the MIDL for it to form the interface to the dll in the right way (this seems to be the essence of COM).
The original link is dead. https://learn.microsoft.com/en-us/cpp/preprocessor/hash-import-directive-cpp?view=vs-2019 seems to be the new URL.
In the link that you listed a key sentence is "#import creates two header files that reconstruct the type library contents in C++ source code". When you #import MSO.DLL you are importing a type library to your project (not to your cpp file) and it creates the necessary COM interface definitions. So you don't need to provide additional information.
But there are probably other files you need to #import in order to use Office applications, depending on what you are trying to do.
I currently have a C# project that uses a 32 bit dll. What I am trying to do is to use the dll in a C++ project , unfortunately the dll referenced in the project does not come with a .h or .lib file so I am confused on how I could access the classes in the dll or use the dll file in my project in C++ (Visual Studio 2010) . I read here that if a dll file contains classes its a good chance it might be a COM component.Any suggestions on what I should be looking at in order to integrate and consume methods and objects in that dll.
Update:
I checked if it was a COM by doing an import statement. However I get a "cannot find .tlb file". Then I decided to use dependency walker to check for any exported methods (objects)it seems there are none. I clicked on the main file (which has been highlighted) and couldn't see any exported functions. Any hints on what I should check for next ?. Here is what I get from dependency walker.
With only a .dll and without a corresponding .h or .exp, one place that you might try looking would be the exports table. Tools such as Dependency Walker can show you this information.
One caveat with Dependency Walker is that you'll want to use the right version (x86 or x86_64) for the binary (your DLL). If you're not sure, pick one version and try loading it. Under the CPU column, middle panel, look to see if it says "x64" or "x86" to determine which one you should be using.
With the provided screenshot of Dependency Walker (indicating a dependency on MSCOREE.DLL), I agree with Eugene - this is most likely a .NET library, not a COM library. You will want to check one of the other questions about calling .NET managed code from C/C++.
The dll is most likely a .Net assembly (seeing that it imports mscoree.dll), so you probably want this: How do I call a .NET assembly from C/C++?
Background: Vendor has provided me ActiveX Dll, no header files or .tlb file or anything such.
I am using Visual Stdio 2010 and using win32 C++.
The problem I am facing is how to load or reference dll?
I cannot reference the dll through solution explorer because it is unmanaged project.
When I try to use #import, it give me compile error saying XXX.tlb file not found. But I don't have .tlb type file.
The other option I tried was to open the dll with OLE viewer and copy the dll definitions and then paste in .idl extension file I created with Visual Studio. Then I executed midl on the idl file to create .h file but that did not help either. When I try use the classes, its gives me "abstract classes cannot be used or referenced" error.
There are other questions asked on the matter but not straight forward and the answers are not marked as answered or upvoted.
I want to know what are the different methods available to load the ActiveX dll in win32 C++ project in visual studio 2010 and which one should be preferred when? If there is a thread that actually addresses my issue please point me to that.
Thanks
If you are able to see the interface definitions using OLE View it means that the type library is embedded into the dll resources. So if you use #import "YourActiveX.dll" it should work.
You need
Register the COM (Active X) component in windows using regsvr32 : regsvr32 my_dll.dll
Then use COM to interact with the component. This is a good tutorial.
I have imported an ActiveX library into my project in Visual Studio 2008 using:
#import "TeeChart8.ocx" named_guids
Now I would like to create objects exposed by the ActiveX library. However, I am having trouble understanding the API.
There are two files that were created after I built the project with the #import, a .tli file and a .tlh file.
In the .tlh file there is the following line:
_COM_SMARTPTR_TYPEDEF(ITChart, __uuidof(ITChart));
I can see ITChart when I open the ActiveX library TeeChart8.ocx in the ITypeLib Viewer (Oleview). Also, if I type ITChartPtr->Invoke into my code, intellisense shows me that there are a whole bunch of parameters that need to be filled.
Essentially, I would like to know how to instantiate an ActiveX object and where I have to look to get the information I need?
Maybe not enough to create ActiveX function CoCreateInstance.
ActiveX must be correctly initialized (Theory can be found here ActiveX Controls Overviews and Tutorials :-)
The easiest way is to use CAxWindow (ATL Framework)
Here, collected various information on how to create ActiveX controls
When it's a simple COM object, you can use the following (assuming a coclass named TChart to go with the interface named ITChart):
ITChartPtr chart(__uuidof(TChart));
For more information on using the ITChartPtr type defined by the _COM_SMARTPTR_TYPEDEF macro in the .tlh file generated by the #import statement, see com_ptr_t.
If it's a full ActiveX control, there is more to it as Victor said in his answer.
Look up the function CoCreateInstance in your API docs.