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Error output in the web browser when starting a Blazor-Server application created with "abp suite" #5108


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karl.ettinger@energieag.at created

When creating a Blazor-Server application via "abp suite" (V7.2.1), without any additional code, when starting the created web application, the error below is displayed in the web browser (Edge, Chrome). If I then click on "Reload" the web application is started.

  • ABP Framework version: v7.2.2
  • UI type: Blazor
  • DB provider: EF Core
  • Exception message and stack trace: blazor.server.js?_v=638153017680000000:1 [2023-05-22T15:09:45.739Z] Information: Normalizing '_blazor' to 'https://localhost:44336/_blazor'. blazor.server.js?_v=638153017680000000:1 [2023-05-22T15:09:45.854Z] Information: WebSocket connected to wss://localhost:44336/_blazor?id=Y3_rJ1QdR9rsJLkWvBwskg. blazor.server.js?_v=638153017680000000:1 [2023-05-22T15:09:46.768Z] Error: System.NullReferenceException: Object reference not set to an instance of an object. at Volo.Abp.AspNetCore.Components.Web.LeptonXTheme.Components.ApplicationLayout.SideMenu.Navigation.MobileNavbar.BuildRenderTree(RenderTreeBuilder __builder) at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException) log @ blazor.server.js?_v=638153017680000000:1 blazor.server.js?_v=638153017680000000:1 [2023-05-22T15:09:46.769Z] Information: Connection disconnected. blazor.server.js?_v=638153017680000000:1 Uncaught (in promise) Error: Invocation canceled due to the underlying connection being closed. at Ft._connectionClosed (blazor.server.js?_v=638153017680000000:1:76250) at Ft.connection.onclose (blazor.server.js?_v=638153017680000000:1:67065) at Nt._stopConnection (blazor.server.js?_v=638153017680000000:1:62559) at transport.onclose (blazor.server.js?_v=638153017680000000:1:60297) at At._close (blazor.server.js?_v=638153017680000000:1:52510) at At.stop (blazor.server.js?_v=638153017680000000:1:52130) at Nt._stopInternal (blazor.server.js?_v=638153017680000000:1:55448) at async Nt.stop (blazor.server.js?_v=638153017680000000:1:55258) at async Ft.stop (blazor.server.js?_v=638153017680000000:1:69730)
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4 Answer(s)
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    maliming created
    Support Team Fullstack Developer

    hi

    Does this error occur every time?

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    karl.ettinger@energieag.at created

    hi yes

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    maliming created
    Support Team Fullstack Developer

    hi

    Please share your project, Thanks

    liming.ma@volosoft.com

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    maliming created
    Support Team Fullstack Developer

    hi

    Add MyMobileNavbar to your blazor project. We will fix that in the next version. Your question credit is refunded.

    using System.Collections.Generic;
    using Volo.Abp.AspNetCore.Components.Web.LeptonXTheme.Components.ApplicationLayout.SideMenu.Navigation;
    using Volo.Abp.AspNetCore.Components.Web.LeptonXTheme.Navigation;
    using Volo.Abp.DependencyInjection;
    
    namespace EagEz.Test.Blazor;
    
    [Dependency(ReplaceServices = true)]
    [ExposeServices(typeof(MobileNavbar), typeof(MyMobileNavbar))]
    public class MyMobileNavbar : MobileNavbar
    {
        public MyMobileNavbar()
        {
            SelectedMenuItems = new List<MenuItemViewModel>();
        }
    }
    
    
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Made with ❤️ on ABP v10.8.0-preview. Updated on October 05, 2026, 11:32
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