Hello,
Welcome to Microsoft Q&A!
The code you post is not the correct way to find add-on products. Generally, we use the code you post to check if the user owns an add-on or the app.
Could you please try to get the add-on product information first?
You could refer to the following code:
if (context == null)
{
context = StoreContext.GetDefault();
// If your app is a desktop app that uses the Desktop Bridge, you
// may need additional code to configure the StoreContext object.
// For more info, see https://aka.ms/storecontext-for-desktop.
}
// Specify the kinds of add-ons to retrieve.
string[] productKinds = { "Durable" };
List<String> filterList = new List<string>(productKinds);
// Specify the Store IDs of the products to retrieve.
string[] storeIds = new string[] { "9NBLGGH4TNMP", "9NBLGGH4TNMN" };
StoreProductQueryResult queryResult =
await context.GetStoreProductsAsync(filterList, storeIds);
You could get more information about how to get add-on product information from this document: Get info for add-ons with known Store IDs that are associated with the current app
Thank you.