Re: Trying to use unmanaged with C#

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In article <eLbTd34SHHA.920@xxxxxxxxxxxxxxxxxxxx>,
EdisonCPP@xxxxxxxxxxxxxxxxx says...
Hi,

My company has a large library of COM objects we've been using for years,
it's massive,
re-writing would take months to years.

One of these objects has a method that looks something like this:

HRESULT EnumItems(IUnkown* pUnk, VARIANT Param);

The IUnknown is a callback, where you would have done something like this:

class CCallback : public ICallbackInterface
{
//Implement dummy Release and AddRefs, supply a good
QueryInterface()

HRESULT MyCallback(LONG ValueNeeded1, BSTR ValueNeeded2, VARIANT
Param)
{
//do something with supplied information
return S_OK;
}
//...
};

CCallback* pCb = new CCallback;
pObj->EnumItems((IUnknown*)pCb, this);

internally it Queries for ICallbackInterface and feeds data to the callback.

Now I need to use this in my C# ASP.NET site. So I made something like
this:

//ref COM obj and convert to managed dll.
using System.Runtime.InteropServices;
using MyObjLib;

[ComVisible(true)] //added with no difference after getting error
public class CallbackClass : CallbackInterface
{
public void MyCallback(int ValueNeeded1, string ValueNeeded2, object
Param)
{
//deal with it
}
};

CallbackClass cc = new CallbackClass;
pObj.EnumItems(cc, this);

Did you also mark the assembly as COMVisible? Check out your
AssemblyInfo.cs.

--
Patrick Steele
http://weblogs.asp.net/psteele
.

Relevant Pages

  • Trying to use unmanaged with C#
    ... HRESULT EnumItems(IUnkown* pUnk, VARIANT Param); ... class CCallback: public ICallbackInterface ... HRESULT MyCallback(LONG ValueNeeded1, BSTR ValueNeeded2, VARIANT ... public class CallbackClass: CallbackInterface ...
    (microsoft.public.dotnet.framework.interop)
  • Trying to use unmanaged with C#
    ... class CCallback: public ICallbackInterface ... public class CallbackClass: CallbackInterface ... public void MyCallback(int ValueNeeded1, string ValueNeeded2, object ... for IDispatch or class interfaces are disallowed. ...
    (microsoft.public.dotnet.general)