- 1 year ago
How to get a meaningful value for PROPERTYKEY from OnPropertyValueChanged()
In order to obtain a meaningful value for PROPERTYKEY
in the OnPropertyValueChanged
method, you can use the following approach:
Use the
IPropertyStore
interface:OnPropertyValueChanged
typically provides anIPropertyStore
interface pointer as a parameter. You can obtain thePROPERTYKEY
value from this interface.Get the
IPropertyDescription
: You can use theGetPropertyDescription
method of theIPropertyStore
interface to retrieve theIPropertyDescription
object associated with thePROPERTYKEY
. This object contains metadata about the property.Get the property's display name: Using the
IPropertyDescription
interface, you can call theGetDisplayName
method to retrieve the display name of the property. This will give you a meaningful value that you can use for logging or displaying to the user.
Here's an example code snippet demonstrating this approach:
cppvoid OnPropertyValueChanged(IPropertyStore* pPropStore, PROPERTYKEY propKey)
{
IPropertyDescription* pPropDesc = nullptr;
HRESULT hr = pPropStore->GetPropertyDescription(propKey, IID_PPV_ARGS(&pPropDesc));
if (SUCCEEDED(hr))
{
PWSTR displayName = nullptr;
hr = pPropDesc->GetDisplayName(&displayName);
if (SUCCEEDED(hr))
{
// Use the display name for logging or displaying to the user
wprintf(L"Property Key: %s\n", displayName);
CoTaskMemFree(displayName);
}
pPropDesc->Release();
}
}
In this example, the OnPropertyValueChanged
method receives an IPropertyStore* pPropStore
and a PROPERTYKEY propKey
as parameters. It obtains the IPropertyDescription
object associated with the PROPERTYKEY
using GetPropertyDescription
, and then retrieves the display name using GetDisplayName
. The display name can be used for logging or displaying to the user.
Make sure to handle any error conditions appropriately by checking the return values of the various function calls.
Note: This example assumes you already have the necessary COM interfaces and objects set up for property handling.