Error using GoToAsync

Question

Hi,

I am trying to show my ContentPage in MAUI but getting below error:

System.NullReferenceException: Object reference not set to an instance of an object.
at xxx.Mobile.OnBoarding.MyCountryTapGestureRecognizer_Tapped(Object sender, TappedEventArgs e) in /Users/jassim/Projects/xxx/xxx/Mobile/OnBoarding.xaml.cs:129
at at Microsoft.Maui.Controls.TapGestureRecognizer.SendTapped(View sender, Func2 getPosition) at at Microsoft.Maui.Controls.Platform.GestureManager.ProcessRecognizerHandlerTap(WeakReference weakEventTracker, WeakReference weakRecognizer, CGPoint originPoint, Int32 uiTapGestureRecognizerNumberOfTapsRequired, UITapGestureRecognizer uITapGestureRecognizer) at at Microsoft.Maui.Controls.Platform.GestureManager.<>c__DisplayClass24_0.<CreateTapRecognizer>b__0(UITapGestureRecognizer sender) at at UIKit.UIGestureRecognizer.Callback1[[UIKit.UITapGestureRecognizer, Microsoft.iOS, Version=16.0.700.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065]].Activated(UITapGestureRecognizer sender)
at at UIKit.UIApplication.UIApplicationMain(Int32 argc, String[] argv, IntPtr principalClassName, IntPtr delegateClassName)
at at UIKit.UIApplication.Main(String[] args, Type principalClass, Type delegateClass)
at xxx.Program.Main(String[] args) in /Users/jassim/Projects/xxx/xxx/Platforms/iOS/Program.cs:13

In my AppShell:

namespace xxx.Mobile;  
  
public partial class AppShell : Shell  
{  
	public AppShell()  
	{  
		InitializeComponent();  
  
        Routing.RegisterRoute(nameof(Mobile.Country), typeof(Mobile.Country));  
    }  
}  

and then:

async void MyCountryTapGestureRecognizer_Tapped(System.Object sender, Microsoft.Maui.Controls.TappedEventArgs e)  
{  
    await Shell.Current.GoToAsync($"Mobile.Country");  
}  

Kindly help...

Thanks.
Jassim

Answer 1

Hello,

I noticed that you used nameof(Mobile.Country) to register the shell route, and called it by Shell.Current.GoToAsync($"Mobile.Country").

As a matter of fact, when you use nameof(Mobile.Country), the value of it would be the class name Country, not Mobile.Country.

Therefore, it should be the cause of your issue.

You could use Shell.Current.GoToAsync($"{nameof(Mobile.Country)}") to execute the navigation event.

Best Regards,

Alec Liu.

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