Overridden functions for IAccessible interface do not work in cwnd-drived class

Question

I have a button called CWnd -derived class named and want to use the CWnd accessibility CWnd , I redefine this function in my class:

 virtual HRESULT get_accName(VARIANT varChild, BSTR *pszName); virtual HRESULT get_accChildCount(long *pcountChildren); virtual HRESULT get_accDefaultAction(VARIANT varChild, BSTR *pszDefaultAction); virtual HRESULT get_accDescription(VARIANT varChild, BSTR *pszDescription); virtual HRESULT get_accKeyboardShortcut(VARIANT varChild, BSTR *pszKeyboardShortcut); virtual HRESULT get_accParent(IDispatch **ppdispParent); virtual HRESULT get_accRole(VARIANT varChild, VARIANT *pvarRole); virtual HRESULT get_accState(VARIANT varChild, VARIANT *pvarState); virtual HRESULT get_accValue(VARIANT varChild, BSTR *pszValue); 

When I run the program and set a break in the implementation of any of these functions, the program does not introduce these functions and instead uses the parent function, can someone help me?

get_accName implementation:

 HRESULT Button::get_accName(VARIANT varChild, BSTR *pszName) { //*pszName = SysAllocString(lpstrTitle); return S_OK; } 

I call EnableActiveAccessibility() in the constructor of this class, but it still does not work.

Answer 1

Have you tried something like:

 class CWnd { virtual HRESULT get_accChildCount(long *pcountChildren); }; class Button : public CWnd { virtual HRESULT get_accChildCount(long *pcountChildren) { HRESULT childCount = CWnd:get_accChildCount(long *pcountChildren); //you can use the value from the ancestor class if it is of any use //to you or add your own code childCount = 1234; return childCount; } }; 

Answer 2

You may be misusing these redundant methods. Try renaming override. This can make everything clearer and indicate that something is wrong. The following is an example implementation.

 ref class Base { public: virtual void Boo() { Show("Base::Boo"); } }; ref class Derived : Base { public: //Overrides Base::Boo virtual void Woo() = Base::Boo { Show("Derived::Woo"); } }; 

Call it like:

 void _tmain() { Base* r = new Derived(); Derived* d = dynamic_cast<Derived*>(r); d->Woo(); } 

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