Calling Managed Code from Unmanaged code

  • Thread starter Thread starter Roy Chastain
  • Start date Start date
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Roy Chastain

I have a legacy application that currently loads an unmanaged (legacy) DLL via LoadLibrary, finds some entry points in it and then
calls them.

I would like to replace the unmanaged DLL with a managed DLL.
I have created a DLL with C++ that has the managed code. It also has unmanaged entry points that mirror the existing legacy DLL.

My problem is that I don't know how to transition to the managed code in this DLL.

I have found CorBindToRuntimeEx but that is as far as I have gotten.

My thinking is that it should go something like this

__gc class ManagedControl
{
public:
void Method1 (void);
void Method2 (void);
}

#pragma unmanaged

static gcroot<ManagedControl*> mc;

__declspec(dllexport) BOOL __stdcall umCreateControl (void)
{
HRESULT result;
ICorRuntimeHost *pHost = NULL;
result = CorBindToRuntimeEx(NULL,NULL,0,CLSID_CorRuntimeHost,IID_ICorRuntimeHost,(void **)&pHost);
/*
Do something to instantiate the managed class that represents the object being used
store that result in mc
*/
return TRUE;
}

Then in the other entry points I would 'simply' call the corresponding method on the managed class instance (mc)
hopefully by something that looks like

__declspec(dllexport) void__stdcall umMethod1 (void)
{
mc->Method1();
}

etc.

Thanks for getting me to the next step.
 
Roy Chastain said:
I have a legacy application that currently loads an unmanaged (legacy) DLL
via LoadLibrary, finds some entry points in it and then
calls them.

I would like to replace the unmanaged DLL with a managed DLL.
I have created a DLL with C++ that has the managed code. It also has
unmanaged entry points that mirror the existing legacy
Click to expand...

I don't really know how to host the runtime, so I would build expose a COM
interface on the .NET component, then from unmanaged code simply use COM,
and the COM-interop stuff will take care of everyting for me.

Again, I'm not sure if that's the best way, but it's easy and it will work.

David
 
Well, it might be easy for you, but it is not for me.
I have never really mastered COM.
I don't have any idea how to start to turn a managed DLL into a COM object.
 
Thanks for the pointer. I was already looking at that, but unfortunately my level of knowledge of COM makes most of that new
information and new technology. I would really rather spend the time working on the CLR hosting.

Hopefully someone out there can give me a little boost on that one.

Thanks.

If you haven't already looked here, then this would be a good place to
start:

Exposing .NET Framework Components to COM:
http://msdn.microsoft.com/library/d.../cpconexposingnetframeworkcomponentstocom.asp

hope that helps..
Imran.

Roy Chastain said:
Well, it might be easy for you, but it is not for me.
I have never really mastered COM.
I don't have any idea how to start to turn a managed DLL into a COM object.
Click to expand...
Click to expand...
 
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