C#•2mo ago

Blazor NavigationManager throws Unspecified navigation exeption.

So i've just started to learn Blazor. I found that when i try to use the NavigationManager from a form (OnValidSubmit), then it throws: Microsoft.AspNetCore.Components.NavigationException: 'Exception_WasThrown' I have not edited any of the setup (program.cs), so i might just be a bug in the framework as there is some bugs on the navigation manager. I have not been able to find any cases exactly like this on their github. It only throws the exception in Debug, and if i continue, the navigation is executed correctly. I have also tried to "hack", by using NavigationManager.NavigateTo() with the current page as parameter, throws same error. Does anyone know if this is a known error and if there might be a workaround (or if there is something i am missing). Code

<EditForm 
    Model="server" 
    FormName="@($"form-server-{server.ServerId}")" 
    OnValidSubmit="@(() => {DeleteServer(server.ServerId);})">
    <button type="submit" class="btn btn-primary">Delete</button>
</EditForm>

<EditForm 
    Model="server" 
    FormName="@($"form-server-{server.ServerId}")" 
    OnValidSubmit="@(() => {DeleteServer(server.ServerId);})">
    <button type="submit" class="btn btn-primary">Delete</button>
</EditForm>

private void DeleteServer(int serverId)
{
    if (serverId > 0)
    {
        ServerRepository.DeleteServer(serverId);
        NavigationManager.Refresh();
    }
}

private void DeleteServer(int serverId)
{
    if (serverId > 0)
    {
        ServerRepository.DeleteServer(serverId);
        NavigationManager.Refresh();
    }
}

Exception: See added image See first comment for stacktrace.

4 Replies

BlueHelmet•2mo ago

tacktrace:

 at Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.NavigateToCore(String uri, NavigationOptions options)
   at Microsoft.AspNetCore.Components.NavigationManager.Refresh(Boolean forceReload)
   at ServerManagement.Components.Pages.Servers.DeleteServer(Int32 serverId) in C:\Repos\BlazorDeepDive\ServerManagement\Components\Pages\Servers.razor:line 53
   at ServerManagement.Components.Pages.Servers.<>c__DisplayClass0_0.<BuildRenderTree>b__0() in C:\Repos\BlazorDeepDive\ServerManagement\Components\Pages\Servers.razor:line 35
   at Microsoft.AspNetCore.Components.EventCallbackWorkItem.InvokeAsync[T](MulticastDelegate delegate, T arg)
   at Microsoft.AspNetCore.Components.ComponentBase.Microsoft.AspNetCore.Components.IHandleEvent.HandleEventAsync(EventCallbackWorkItem callback, Object arg)
   at Microsoft.AspNetCore.Components.EventCallback`1.InvokeAsync(TValue arg)
   at Microsoft.AspNetCore.Components.Forms.EditForm.<HandleSubmitAsync>d__46.MoveNext()

 at Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.NavigateToCore(String uri, NavigationOptions options)
   at Microsoft.AspNetCore.Components.NavigationManager.Refresh(Boolean forceReload)
   at ServerManagement.Components.Pages.Servers.DeleteServer(Int32 serverId) in C:\Repos\BlazorDeepDive\ServerManagement\Components\Pages\Servers.razor:line 53
   at ServerManagement.Components.Pages.Servers.<>c__DisplayClass0_0.<BuildRenderTree>b__0() in C:\Repos\BlazorDeepDive\ServerManagement\Components\Pages\Servers.razor:line 35
   at Microsoft.AspNetCore.Components.EventCallbackWorkItem.InvokeAsync[T](MulticastDelegate delegate, T arg)
   at Microsoft.AspNetCore.Components.ComponentBase.Microsoft.AspNetCore.Components.IHandleEvent.HandleEventAsync(EventCallbackWorkItem callback, Object arg)
   at Microsoft.AspNetCore.Components.EventCallback`1.InvokeAsync(TValue arg)
   at Microsoft.AspNetCore.Components.Forms.EditForm.<HandleSubmitAsync>d__46.MoveNext()

Zendist•2mo ago

It throws, but still works? Huh? Are you catching an exception that gets caught by the framework and is ignored, perhaps?

friedice•2mo ago

I personally never ran into that issue. What's your .razor look like? Are you using WASM, server, or auto?

BlueHelmet•5w ago

I found that you could disable that type if exeption in debug mode. Apparently it is a known thing that the navigator throws an exception and handles it somewhere else. When running without debugging no errors occurs. For now i am not using any interactivity (why i need to call the refresh function)

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Blazor NavigationManager throws Unspecified navigation exeption.