CODEWITHSUNDEEP
c#.netcommarshallingcom-interop
Bojan Vukasovic
Bojan Vukasovic

Reputation: 2268

Typesafe COM component with late binding in dotnet

I have some libraries in x32 that I need to call from x64 process. Googling around, I found the best way to do this is using COM components. I created 3 projects in c#:

I also registered this COM component (Dll32) in registry (manually adding Wow6432Node paths, and added DllSurrogate props in order to be able to call this x32 from x64 process)

I call this from WinForms project using following code:

Type ComType = Type.GetTypeFromCLSID(new Guid("85840403-68F7-4B39-B015-7ED3506FD06B"));
dynamic c2 = Activator.CreateInstance(ComType);
string dd = c2.someMethod("asd");
MessageBox.Show(dd);

Now this thing is working, but what i wanted to do is to be able to reference BaseDll inside WinForms project and have the following line working:

BaseInter c2 = (BaseInter) Activator.CreateInstance(ComType);

The exception that I get here is:

System.InvalidCastException: 'Unable to cast COM object of type 'System.__ComObject'
to interface type 'BaseDll.BaseInter'. This operation failed because the 
QueryInterface call on the COM component for the interface with IID 
'{40E88E31-DFEA-357E-8A97-E5F0077666C2}' failed due to the following error:
 No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).'

Is the problem here the fact that interface included in WinForms app is compiled for x64 and is not the same as the one in x32 Dll32 project? If I compile WinForms as x32, then this casting code also works without the problem.

UPDATE

BaseInter

public interface BaseInter
{
    string someMethod(String ime);
}

Dll32

[ComVisible(true)]
[Guid("85840403-68F7-4B39-B015-7ED3506FD06B")]
public class JaviSe : BaseInter
{
    public string someMethod(string ime)
    {
        return "Hi from 32 " + ime;
    }
}

Reigstry entries (beside the ones that VS already inserted):

REGEDIT4

[HKEY_CLASSES_ROOT\Wow6432Node\Dll32.JaviSe]
@="Dll32.JaviSe"

[HKEY_CLASSES_ROOT\Wow6432Node\Dll32.JaviSe\CLSID]
@="{85840403-68F7-4B39-B015-7ED3506FD06B}"

[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{85840403-68F7-4B39-B015-7ED3506FD06B}]
@="Dll32.JaviSe"
"AppID"="{85840403-68F7-4B39-B015-7ED3506FD06B}"

[HKEY_CLASSES_ROOT\Wow6432Node\AppID\{85840403-68F7-4B39-B015-7ED3506FD06B}]
"DllSurrogate"=""

[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{85840403-68F7-4B39-B015-7ED3506FD06B}\InprocServer32]
@="mscoree.dll"
"ThreadingModel"="Both"
"Class"="Dll32.JaviSe"
"Assembly"="Dll32, Version=1.0.0.0, Culture=neutral, PublicKeyToken=143740cba1c5c559"
"RuntimeVersion"="v4.0.30319"
"CodeBase"="file:///C:/Users/default.DESKTOP-VNP7D7O/source/repos/SurogateTests/Dll32/bin/Debug/Dll32.dll"

[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{85840403-68F7-4B39-B015-7ED3506FD06B}\InprocServer32\1.0.0.0]
"Class"="Dll32.JaviSe"
"Assembly"="Dll32, Version=1.0.0.0, Culture=neutral, PublicKeyToken=143740cba1c5c559"
"RuntimeVersion"="v4.0.30319"
"CodeBase"="file:///C:/Users/default.DESKTOP-VNP7D7O/source/repos/SurogateTests/Dll32/bin/Debug/Dll32.dll"

[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{85840403-68F7-4B39-B015-7ED3506FD06B}\ProgId]
@="Dll32.JaviSe"

[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{85840403-68F7-4B39-B015-7ED3506FD06B}\Implemented Categories\{62C8FE65-4EBB-45E7-B440-6E39B2CDBF29}]

Upvotes: 0

Views: 101

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