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COM ATL programming

Started by cutesiham Jan 17, 2003 at 10:40 PM 3 replies 550+ views

Original Post

Jan 17, 2003 at 10:40 PM

Hi i have a problem in my COM ATL Programming. (I m writing OCX file for VB) can i have a function return multiple value? Let say i have function named CalcVariance(a,avg,var) which takes in 3 arguments and it is supposed to return the value of avg and var. so in the idl file, i wrote [id(19), helpstring("method CalcVariance")] HRESULT CalcVariance([in]vObjFeatures vFeature, [out]double* pAvg,[out]double* pVar); Hence, did i declare the right thing? in Vb i call using this way: Dim nAvg,nVar as double VsBlobObject1.FeatureVariance i, nAvg, nVar But the VB code couldn''t execute the function as it gave me "Type Mismatch" error code. so can anyone teach me how to write this function.... from damian

Shannon Barber

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368

Shannon Barber

Jan 17, 2003 at 11:36 PM

What is vObjFeatures?

cutesiham

Author

cutesiham

Jan 17, 2003 at 11:42 PM

the "vObjFeatures" is the enum value. integer type.

this variable doesn;t give me the error.

Solo

Jan 18, 2003 at 4:29 PM

The IDL definition you posted is for a method called CalcVariance. The VB code you posted calls FeatureVariance. Typo?

[edited by - Solo on January 18, 2003 5:30:03 PM]

cutesiham

Author

cutesiham

Jan 19, 2003 at 7:52 PM

Ouuuppps...sorry..it is typo mistake.

It should be
in Vb i call using this way:
Dim nAvg,nVar as double
VsBlobObject1.CalcVariance i, nAvg, nVar

thanks

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