How can I allow in-app purchases through my .NET MAUI application? - maui

Question

I'm looking for documentation on this and I'm not finding it.
The main things I need to accomplish are:
Allow the user to purchase an add-on through the Microsoft Store.
Determine if they've already purchased an add-on so the appropriate application features can be enabled.
These two things can be accomplished easily for a UWP app as described here:
https://learn.microsoft.com/en-us/windows/uwp/monetize/enable-subscription-add-ons-for-your-app#code-examples
But I can't find an equivalent for .NET MAUI.

Answer 1

So in fact you can use the UWP code examples from Microsoft. The trick is to wrap everything that's Windows specific in a statement like this:
#if WINDOWS
...
#endif
So my code looks like this:
#if WINDOWS
using Windows.Services.Store;
#endif
namespace MyProject.Data
{
public class AddOnService
{
#if WINDOWS
private StoreContext context = null;
StoreProduct subscriptionStoreProduct;
// Assign this variable to the Store ID of your subscription add-on.
private string subscriptionStoreId = "INSERT-STORE-ID";
public async Task<bool> SetupSubscriptionInfoAsync()
{
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.
}
bool userOwnsSubscription = await CheckIfUserHasSubscriptionAsync();
if (userOwnsSubscription)
{
// Unlock all the subscription add-on features here.
return true;
}
// Get the StoreProduct that represents the subscription add-on.
subscriptionStoreProduct = await GetSubscriptionProductAsync();
if (subscriptionStoreProduct == null)
{
return true;
}
// Check if the first SKU is a trial and notify the customer that a trial is available.
// If a trial is available, the Skus array will always have 2 purchasable SKUs and the
// first one is the trial. Otherwise, this array will only have one SKU.
StoreSku sku = subscriptionStoreProduct.Skus[0];
if (sku.SubscriptionInfo.HasTrialPeriod)
{
// You can display the subscription trial info to the customer here. You can use
// sku.SubscriptionInfo.TrialPeriod and sku.SubscriptionInfo.TrialPeriodUnit
// to get the trial details.
}
else
{
// You can display the subscription purchase info to the customer here. You can use
// sku.SubscriptionInfo.BillingPeriod and sku.SubscriptionInfo.BillingPeriodUnit
// to provide the renewal details.
}
// Prompt the customer to purchase the subscription.
await PromptUserToPurchaseAsync();
return false;
}
private async Task<StoreProduct> GetSubscriptionProductAsync()
{
// Load the sellable add-ons for this app and check if the trial is still
// available for this customer. If they previously acquired a trial they won't
// be able to get a trial again, and the StoreProduct.Skus property will
// only contain one SKU.
StoreProductQueryResult result =
await context.GetAssociatedStoreProductsAsync(new string[] { "Durable" });
if (result.ExtendedError != null)
{
System.Diagnostics.Debug.WriteLine("Something went wrong while getting the add-ons. " +
"ExtendedError:" + result.ExtendedError);
return null;
}
// Look for the product that represents the subscription.
foreach (var item in result.Products)
{
StoreProduct product = item.Value;
if (product.StoreId == subscriptionStoreId)
{
return product;
}
}
System.Diagnostics.Debug.WriteLine("The subscription was not found.");
return null;
}
private async Task<bool> CheckIfUserHasSubscriptionAsync()
{
StoreAppLicense appLicense = await context.GetAppLicenseAsync();
// Check if the customer has the rights to the subscription.
foreach (var addOnLicense in appLicense.AddOnLicenses)
{
StoreLicense license = addOnLicense.Value;
if (license.SkuStoreId.StartsWith(subscriptionStoreId))
{
if (license.IsActive)
{
// The expiration date is available in the license.ExpirationDate property.
return true;
}
}
}
// The customer does not have a license to the subscription.
return false;
}
private async Task PromptUserToPurchaseAsync()
{
// Request a purchase of the subscription product. If a trial is available it will be offered
// to the customer. Otherwise, the non-trial SKU will be offered.
StorePurchaseResult result = await subscriptionStoreProduct.RequestPurchaseAsync();
// Capture the error message for the operation, if any.
string extendedError = string.Empty;
if (result.ExtendedError != null)
{
extendedError = result.ExtendedError.Message;
}
switch (result.Status)
{
case StorePurchaseStatus.Succeeded:
// Show a UI to acknowledge that the customer has purchased your subscription
// and unlock the features of the subscription.
break;
case StorePurchaseStatus.NotPurchased:
System.Diagnostics.Debug.WriteLine("The purchase did not complete. " +
"The customer may have cancelled the purchase. ExtendedError: " + extendedError);
break;
case StorePurchaseStatus.ServerError:
case StorePurchaseStatus.NetworkError:
System.Diagnostics.Debug.WriteLine("The purchase was unsuccessful due to a server or network error. " +
"ExtendedError: " + extendedError);
break;
case StorePurchaseStatus.AlreadyPurchased:
System.Diagnostics.Debug.WriteLine("The customer already owns this subscription." +
"ExtendedError: " + extendedError);
break;
}
}
#else
public async Task<bool> SetupSubscriptionInfoAsync()
{
return false;
}
#endif
}
}
I'll be modifying this some to suit my needs but I was able to debug it and step through the code to verify that the code is indeed executing as expected on Windows.