Listing available products

We need to present the details about what products or subscriptions are available for purchase so that the users can verify what they want before making any purchases.

How to do it...

We can request a list of Product instances using the QueryInventoryAsync() method:

1. The QueryInventoryAsync() method returns the product details when invoked with the desired product IDs and the Product ItemType instance:

   var productIds = new string[] {
     "managed.one",
     "managed.two"
   };
   var products = await billing.QueryInventoryAsync(
     productIds, ItemType.Product);
   

2. If we have any subscriptions, we can repeat the same process but we will use the Subscription ItemType type this time:

   var productIds = new string[] {
     "subscription.one"
   };
   var subscriptions = await billing.QueryInventoryAsync(
     productIds, ItemType.Subscription);

3. Similar to do the process for all the requests, errors may occur, such as when there is no connectivity. We can respond to these...