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returning safearray of idispatch pointers as variant

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Latest post 06-20-2008 9:55 AM by Gary. 4 replies.

06-19-2008 8:18 AM

rahulr
Joined on 06-05-2008
Posts 2

returning safearray of idispatch pointers as variant

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Hi,

I have a function

STDMETHODIMP CTestComponent::func3(VARIANT* objects)

in my host which is supposed to return an array of IDispatch pointers as a SAFEARRAY

In the proxy the function becomes

void func3(out object dllcomps);

I can return an array of BSTR values but not IDispatch* , get a ArgumentException

Should that be possible?

regards

rahul

06-19-2008 9:02 AM In reply to

Gary
Joined on 07-13-2006
Posts 305

Re: returning safearray of idispatch pointers as variant

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Are you using ProxyGen for VSTA 1.0?

06-19-2008 1:09 PM In reply to

Gary
Joined on 07-13-2006
Posts 305

Re: returning safearray of idispatch pointers as variant

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As documented in Thomas Quinn's blog arrays are passed as value by default. In your particular case, IDispatch* is a reference type. Proxygen will not pass IDispatch* parameters because it violates the transitive closure of types; that is, types that cross from host to add-in and vice versa must be well-defined. This provides security for the host application.

It is possible to work around this issue with a custom contract or a simplified approach to the proxy layer. But if you can pass an array of values, that is the simplest solution.

06-20-2008 9:48 AM In reply to

rahulr
Joined on 06-05-2008
Posts 2

Re: returning safearray of idispatch pointers as variant

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Thanks, Gary.

However, I am able to return a single IDispatch* successfully.

STDMETHODIMP CTestComponent::func2(IDispatch** pD) which maps as public object func2()

Is that difference expected as well? ( array of idispatch is failing but single idispatch succeeds)

If what u say is true -- "types that cross from host to add-in and vice versa must be well-defined..." then whether the data is in an array or not, should it matter?

I may be totally wrong here, please correct me if so..

regards

rahul

06-20-2008 9:55 AM In reply to

Gary
Joined on 07-13-2006
Posts 305

Re: returning safearray of idispatch pointers as variant

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Which version of ProxyGen are you using for func2(IDispatch** pD)?

I will have to confirm, but I'm pretty sure that Array elements are only passed by value with both ProxyGen v1 and v2

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