Control Throws a Null Exception When Hosted on a ContentView

[RuddySantos]

I am very new to this. The requirement I have calls for the webview to be hosted in a control (contentView). The HybridView shows fine and callling JS methods etc works. However, when I close the popup window that is hosting the control there is an object reference not set to an instance of an object exception on the OnHandlerChanged --> NavigationCore.

NOTE: This app uses Mopups for pushing/popping pages.

[peterblazejewicz]

Does it happen with regular MAUI BlazorWebView?

[rsantos16]

We did not try it with the regular BlazorWebView. We are in the process of looking at other solutions but this HybridWebView is the best choice due to our constrains.

[Eilon]

Hi @RuddySantos / @rsantos16 - I tried placing the HybridWebView inside a ContentView and that seemed to work just fine. Do you have a complete repro project that you can share for this?

Or perhaps a full stack trace of the exception?

I saw some places in the code that are possible culprits for a potential bug but it's hard to say without more info.

[johandep]

Hi @Eilon , we face the same issue and this is the stack trace:

at ObjCRuntime.Runtime.ThrowException(IntPtr gchandle) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/ObjCRuntime/Runtime.cs:line 2719
   at UIKit.UIApplication.UIApplicationMain(Int32 argc, String[] argv, IntPtr principalClassName, IntPtr delegateClassName) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line 64
   at UIKit.UIApplication.Main(String[] args, Type principalClass, Type delegateClass) in `/Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line` 96
   at MobileApp.Program.Main(String[] args) in /Users/johan/mobileapp/Platforms/iOS/Program.cs:line 13
2024-11-01 13:59:40.224525+0100 MobileApp[43460:4908687] Unhandled managed exception: Object reference not set to an instance of an object. (System.NullReferenceException)
   at HybridWebView.HybridWebView.get_PlatformWebView()
   at HybridWebView.HybridWebView.NavigateCore(String url)
   at HybridWebView.HybridWebView.Navigate(String url)
   at HybridWebView.HybridWebView.OnHandlerChanged()
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
   at Foundation.NSAsyncSynchronizationContextDispatcher.Apply() in /Users/builder/azdo/_work/1/s/xamarin-macios/src/Foundation/NSAction.cs:line 179

We use the Shell to navigate between pages and when coming back to a page with the HybridWebView component on it, it always crashes in our project.