COM component's C++ client works but .net client doesn't?

[Simon LU]

I have a COM component in ATL, one of its method's IDL define is as the
following:
HRESULT SetValue(long a, [in] long* b,[in]string* c, [in]VARIANT* d,
[out,retval] ConfirmVal e);
here ConfirmVal is a Enum define by IDL.

The VC++ client has no problem to call it by using smart pointer as the
followings:
long a=0;
long b=-1;
CComBSTR c=L"NAME";
d = ICxValuePtr(__uuidof(ICxValue)); //d is another smartpointer, it is a
IDispatch interface in IDL
ConfirmVal e;
ptr->SetValue(a,&b,&c,d,&e)
....

When my C# client calls it as the followings, it throws COMException with
"Unspecified error":
int a=0;
int b=-1;
string c="NAME";
CxValueObject d = new CxValueObject(); //CxValueObject is the class
corresponding to ICxValue interface in the assembly converted by tlbimp.exe
ConfirmVal e;
obj.SetValue(a, ref b, ref c, d, out e); //Throws COMException with
"Unspecified error" here
....

The signature of SetValue in C# in the assembly is void SetValue(int,ref
int,ref string,object,out ConfirmVal).

Can anybody give a clue?

Thanks in advance.

Simon

 

[Kumar Gaurav Khanna [.NET MVP]]

Hi!

Typically, when you TLBIMP a COM class, the class is actually suffixed with
the "Class" string in its .NET version, while the original class name is
actually made to be an interface. So try this:

CxValueObject d = new CxValueObjectClass();

Regards,
Gaurav Khanna

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