AppDelegate.PerformFetch(UIApplication, UIBackgroundFetchResult)': no suitable method found to override

Question

Hi,

I am trying to use background service in .NET MAUI app and here is my AppDelegate:

using Foundation;
using UIKit;
using UserNotifications;

namespace MyApp;

[Register("AppDelegate")]
public class AppDelegate : MauiUIApplicationDelegate
{
    protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();

    protected override async void PerformFetch(UIApplication application, UIBackgroundFetchResult completionHandler)
    {
        // Perform your background fetch here

        completionHandler(UIBackgroundFetchResult.NewData);
    }
}

but I get this error:

/Users/jassim/Projects/MyApp/MyApp/Platforms/iOS/AppDelegate.cs(35,35): Error CS0115: 'AppDelegate.PerformFetch(UIApplication, UIBackgroundFetchResult)': no suitable method found to override (CS0115) (MyApp)

Kindly help..

Thanks

Answer 1

Hello,

This is a known issue reported at GitHub. Please see iOS AppDelegate - PerformFetch override #1419 and iOS AppDelegate - Override for PerformFetch is not available #7957

And it was fixed the in .Net8.0.0-preview.3.8149.

For the usage of App lifecycle, you could refer to App lifecycle - .NET MAUI | Microsoft Learn.

Best Regards,

Wenyan Zhang

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