这是Bug还是我缺少什么？

Question

我才刚刚开始对.net core 2.2应用程序进行本地化，我正在寻找一种从sql数据库中获取区域性的方法。 我正在尝试使用代码在Startup的Configure方法中配置请求本地化对象

import android.os.Bundle;
import android.util.Log;
import com.github.barteksc.pdfviewer.PDFView;
import com.github.barteksc.pdfviewer.listener.OnLoadCompleteListener;
import com.github.barteksc.pdfviewer.listener.OnPageChangeListener;
import com.github.barteksc.pdfviewer.scroll.DefaultScrollHandle;
import com.shockwave.pdfium.PdfDocument;
import java.util.List;






public class ReadingActivity extends Activity  implements OnPageChangeListener,OnLoadCompleteListener {


    private static final String TAG = ReadingActivity.class.getSimpleName();
    public static final String PDF_FILE = "my_book.pdf";


    PDFView pdfView ;
    Integer pageNumber;
    String pdfFileName;

Integer currentPageNumber;
Integer savedPage;







    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_reading);






SharedPreferences mySharedPreferences = getPreferences(Context.MODE_PRIVATE);

savedPage = mySharedPreferences.getInt("retrievedPage",0);

pageNumber = savedPage;







        pdfView = (PDFView)findViewById(R.id.pdfView);
        displayFromAsset(PDF_FILE);


    }










    private void displayFromAsset(String assetFileName) {
        pdfFileName = assetFileName;

        pdfView.fromAsset(PDF_FILE)
                .defaultPage(pageNumber)
                .enableSwipe(true)
                .swipeHorizontal(false)
                .onPageChange(this)
                .enableAnnotationRendering(true)
                .onLoad(this)
                .scrollHandle(new DefaultScrollHandle(this))
                .load();




        }





    @Override
    public void onPageChanged(int page, int pageCount) {

        pageNumber = page;
        setTitle(String.format("%s %s / %s", pdfFileName, page + 1, pageCount));

            }




    @Override
    public void loadComplete(int nbPages) {
        PdfDocument.Meta meta = pdfView.getDocumentMeta();
        printBookmarksTree(pdfView.getTableOfContents(), "-");

    }


    public void printBookmarksTree(List<PdfDocument.Bookmark> tree, String sep) {
        for (PdfDocument.Bookmark b : tree) {

            Log.e(TAG, String.format("%s %s, p %d", sep, b.getTitle(), b.getPageIdx()));

            if (b.hasChildren()) {
                printBookmarksTree(b.getChildren(), sep + "-");
            }
        }
    }



@Override
protected void onStop() {
    super.onStop();

    SharedPreferences mySharedPreferences = getPreferences(Context.MODE_PRIVATE);
    SharedPreferences.Editor myEditor = mySharedPreferences.edit();


savedPage = pdfView.getCurrentPage();
myEditor.putInt("retrievedPage",savedPage);
myEditor.apply();


}

}

我在代码中设置了一个断点，并且看到区域性返回了4个项目，但是对SupportedCultures仅添加了一个项目，而ConfigureServices中的相同代码也可以正常工作。 我在配置服务中使用的代码是

public void Configure(IApplicationBuilder app, IHostingEnvironment env, IStringLocalizerFactory localizerFactory)
    {

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseStatusCodePagesWithReExecute("/Error/{0}");
        }

        string defaultCulture = null;
        var supportedCultures = new List<CultureInfo>();
        using (var scope = app.ApplicationServices.CreateScope())
        {
            var db = scope.ServiceProvider.GetService<IRepository<Language>>();
            defaultCulture = db.FindBy(c => c.IsSelected).FirstOrDefault().Code;
            var langs = db.GetAll().ToList();
            foreach (var item in langs)
            {
                CultureInfo ci = new CultureInfo(item.Code);
                supportedCultures.Add(ci);
            }
        }

        app.UseRequestLocalization(new RequestLocalizationOptions
        {
            DefaultRequestCulture = new RequestCulture(defaultCulture),
            SupportedCultures = supportedCultures,
            SupportedUICultures = supportedCultures
        });

        app.UseStaticFiles();
        app.UseCookiePolicy();
        app.UseSession();
        app.UseAuthentication();

        app.UseMvc();
    }

使用Configure方法中的代码在我的方法上有错误吗？