Calling InvokeAsync(StateHasChanged) causes page to fallback to default culture

[DaveNay]

Describe the bug

In a Blazor Server application, I am updating page data from a background service. This update from the service ultimately ends up calling InvokeAsync(StateHasChanged) in the page. The page is also using IStringLocalizer<T> to provide translations for table headers. When the application runs, the user can select the current culture (e.g. German (de-DE)), and the table is displayed with translated headers. As soon as the background updates begin, the German culture is ignored, and the page is rendered using English (en-US) resources.

My expectation is that calling StateHasChanged will use the proper resources for rendering the page.

To Reproduce

I have created a small application that reproduces this scenario:

https://github.com/DaveNay/Service_Localization_Debugging

In the sample application, you can switch to the FetchData page, and then change the culture to German. You will see that the page is rendered with the de-DE resources. 10 seconds after the application starts, the background updates will begin. As soon as the updates begin, the page is rendered using en-US resources.

Exceptions (if any)

None

Further technical details

• .Net 5.0 (also .Net Core 3.1)
• Visual Studio Pro 16.8.2
• Windows 10 Enterprise 1809
• dotnet_info.txt

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[beppemarazzi]

Found the same issue. Waiting for an official solution, i solved using this workaround:

using System;
using System.Globalization;
using System.Threading.Tasks;

namespace Microsoft.AspNetCore.Components
{
    //https://github.com/dotnet/aspnetcore/issues/28521
    public abstract class ComponentBaseWithCulture : ComponentBase
    {
        private CultureInfo? m_componentUICulture;
        protected override void OnInitialized()
        {
            m_componentUICulture = CultureInfo.CurrentUICulture;
            base.OnInitialized();
        }

        protected Task InvokeAsyncWithCulture(Action workItem)
        {
            return InvokeAsync(() => DispatchWithCulture(workItem));
        }
        private void DispatchWithCulture(Action workItem)
        {
            var prevUICulture = CultureInfo.CurrentUICulture;
            if (m_componentUICulture != null)
                CultureInfo.CurrentUICulture = m_componentUICulture;
            try
            {
                workItem();
            }
            finally
            {
                CultureInfo.CurrentUICulture = prevUICulture;
            }
        }
        protected Task InvokeAsyncWithCulture(Func<Task> workItem)
        {
            return InvokeAsync(() => DispatchWithCulture(workItem));
        }
        private Task DispatchWithCulture(Func<Task> workItem)
        {
            var prevUICulture = CultureInfo.CurrentUICulture;
            if (m_componentUICulture != null)
                CultureInfo.CurrentUICulture = m_componentUICulture;
            try
            {
                return workItem();
            }
            finally
            {
                CultureInfo.CurrentUICulture = prevUICulture;
            }
        }

    }
}