CODEWITHSUNDEEP
c++atlidl
nabegheh95
nabegheh95

Reputation: 305

how to create two ATL interface derived from another?

I have a Dll Project with IDL interfaces. I Want to have to interfaces in my dll that one of them can be derived from other. I created two interfaces with ATL Simple Object Wizard.

[
    object,
    uuid(7359AF6C-6E90-4372-991F-556602CB3977),
    dual,
    nonextensible,
    pointer_default(unique)
]
interface IZInterface : IDispatch{
    [id(1)] HRESULT ZGetStr([out,retval] BSTR* str);
    [id(2)] HRESULT GetSize([in,out] LONG* nSize);
};
[
    object,
    uuid(8CA6DBF2-E402-464D-96AE-3D6642D91E14),
    pointer_default(unique)
]
interface IBClass : IUnknown{
    [] HRESULT Method11([out,retval] LONG* l);
};
library DllStandardLib
{
    importlib("stdole2.tlb");
    [
        uuid(491DF659-012F-4C20-90AA-0CBC5BDE5A68)      
    ]
    coclass ZInterface
    {
        [default] interface IZInterface;
    };
        [
        uuid(43CE897F-17F2-4D45-9098-26B7AEE6EC23)      
    ]
    coclass BClass
    {
        [default] interface IBClass;
    };
};

now, i right click on CZInterface in Class View then Impelement Interface IBClass .

but in continer that is a C# project:

DllStandardLib.ZInterface dd = new DllStandardLib.ZInterface();
dd.Method11();//---> Error: DllStandardLib.ZInterface' does not contain a definition for 'Method11' and no extension method 'Method11' accepting a first argument of type ...

what is the problem in my project? I want the second (derived) interface knows all methods and properties of base interface. please help me!

Upvotes: 0

Views: 1025

Answers (1)

Carsten
Carsten

Reputation: 11626

Best thing is not to use the Object Wizard if you want to achive this. First, define your interfaces:

[
    object,
    uuid(7359AF6C-6E90-4372-991F-556602CB3977),
    dual,
    nonextensible,
    pointer_default(unique)
]
interface IZInterface : IDispatch
{
    [id(1)] HRESULT ZGetStr([out,retval] BSTR* str);
    [id(2)] HRESULT GetSize([in,out] LONG* nSize);
};

[
    object,
    uuid(8CA6DBF2-E402-464D-96AE-3D6642D91E14),
    pointer_default(unique)
]
interface IBClass : IZInterface    // IBClass inherits from IZInterface
{
    [id(3)] HRESULT Method11([out,retval] LONG* l);
};

Then define your class, that implements the specialized interface. Do this within your library:

library DllStandardLib
{
    importlib("stdole2.tlb");

    [
        uuid(43CE897F-17F2-4D45-9098-26B7AEE6EC23)      
    ]
    coclass BClass
    {
        [default] interface IBClass;
    };

    // NOTE: No need for ZInterface coclass.
};

Note that the IZInterface class is not really needed, except you want to provide an separate implementation (= another class).

In order for the QueryInterface-calls to work, you should also add the interface to your COM interface map:

class CBClass : 
    // ...
{
    // ...

BEGIN_COM_MAP(CBClass)
    COM_INTERFACE_ENTRY(IBClass)
    COM_INTERFACE_ENTRY(IZInterface)
END_COM_MAP()

    // ...

    // IBClass-Member
    STDMETHOD(Method11)(LONG* l);    // Implement this in your source file (STDMETHODIMP CBClass::Method11(LONG* l) { return E_NOTIMPL; }
}

To call your IBClass interface members from .NET, you have to create an instance of the right class:

DllStandardLib.BClass bc = new DllStandardLib.BClass();
bc.Method11();

Upvotes: 1

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