IModelPropertyAccessor::GetValue method (dbgmodel.h)

The GetValue method is the getter for the property accessor. It is called whenever a client wishes to fetch the underlying value of the property. Note that any caller which directly gets a property accessor is responsible for passing the key name and accurate instance object (this pointer) to the property accessor's GetValue method.

Syntax

HRESULT GetValue(
  PCWSTR       key,
  IModelObject *contextObject,
  IModelObject **value
);

Parameters

key

The name of the key to get a value for. A caller which fetches a property accessor directly is responsible for passing this accurately.

contextObject

The context object (instance this pointer) from which the property accessor was fetched.

value

The underlying value of the property is returned here.

Return value

This method returns HRESULT that indicates success or failure.

Remarks

Sample Code

// The full implementation class is shown for clarity.
class MyReadOnlyProperty :
    public Microsoft::WRL::RuntimeClass<
        Microsoft::WRL::RuntimeClassFlags<
            Microsoft::WRL::RuntimeClassType::ClassicCom
            >,
        IModelPropertyAccessor
        >
{
public:

    IFACEMETHOD(GetValue)(_In_ PCWSTR /*pwszKey*/, 
                          _In_ IModelObject * /*pContextObject*/, 
                          _COM_Errorptr_ IModelObject **ppValue)
    {
        HRESULT hr = S_OK;
        *ppValue = nullptr;

        VARIANT vtValue;
        vtValue.vt = VT_I4;
        vtValue.lVal = m_value;
        
        ComPtr<IModelObject> spValue;
        hr = GetManager()->CreateIntrinsicObject(ObjectIntrinsic, &vtValue, &spValue);
        if (SUCCEEDED(hr))
        {
            *ppValue = spValue.Detach();
        }

        return hr;
    }

    IFACEMETHOD(SetValue)(_In_ PCWSTR /*pwszKey*/, 
                          _In_ IModelObject * /*pContextObject*/, 
                          _In_ IModelObject * /*pValue*/)
    {
        // We are a read only property.
        return E_NOTIMPL;
    }

    HRESULT RuntimeClassInitialize(_In_ int value)
    {
        m_value = value;
        return S_OK;
    }

private:

    int m_value;
};

Requirements

   
Header dbgmodel.h

See also

IModelPropertyAcessor interface