I used globalization and localization in .net core 2.2 yet and now wanna migrate it to .net core 3.0 preview8.

Here is my code in .net core 2.2:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
//app.UseBrowserLink();
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Error");
app.UseHttpsRedirection();
}

var SupportedCultures = new List<CultureInfo> {
new CultureInfo("en"),
new CultureInfo("zh-Hans"),
new CultureInfo("zh-Hant")
};
var options = new RequestLocalizationOptions
{
DefaultRequestCulture = new RequestCulture("en"),
SupportedCultures = SupportedCultures,
SupportedUICultures = SupportedCultures
};
app.UseRequestLocalization(options);
app.UseStaticFiles();

app.UseStatusCodePagesWithReExecute("/StatusCode/{0}");

var requestProvider = new RouteDataRequestCultureProvider();
options.RequestCultureProviders.Insert(0, requestProvider);

app.UseRouter(routes =>
{
routes.MapMiddlewareRoute("{culture=en}/{*mvcRoute}", subApp =>
{
subApp.UseRequestLocalization(options);

subApp.UseMvc(mvcRoutes =>
{
mvcRoutes.MapRoute(
name: "default",
template: "{culture=en}/{controller=Home}/{action=Index}");
// map the .html suffix
mvcRoutes.MapRoute(
name: "home.html",
template: "{culture=en}/{controller=Home}/{action}.html");
});
});
});
}

And here is my code in .net core 3.0

[Obsolete]
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Home/Error");
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHttpsRedirection();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseCookiePolicy();

var SupportedCultures = new List<CultureInfo> {
new CultureInfo("en"),
new CultureInfo("zh-Hans"),
new CultureInfo("zh-Hant")
};
var options = new RequestLocalizationOptions
{
DefaultRequestCulture = new RequestCulture("zh-Hans"),
SupportedCultures = SupportedCultures,
SupportedUICultures = SupportedCultures
};
app.UseRequestLocalization(options);
var requestProvider = new RouteDataRequestCultureProvider();
options.RequestCultureProviders.Insert(0, requestProvider);
app.UseStaticFiles();

app.UseStatusCodePagesWithReExecute("/StatusCode/{0}");

app.UseRouting();
app.UseCors();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllerRoute(
name: "default",
pattern: "{culture=zh-hans}/{controller=Home}/{action=Index}");
endpoints.MapControllerRoute(
name: "html",
pattern: "{culture=zh-hans}/{controller=Home}/{action}.html");

});

}

The MVC Controller and any other things change a lot and I don't know how to migrate it.

Now the problem is the default language of globalization and localization is 'zh-hans' but not in .net core 3.0 is English. What's more, it seems the globalization and localization do not work also.

The code I wrote before is for changing the globalization and localization by URL, for example, www.microsoft.com/en/ for English, www.microsoft.com/zh-hans for Chinese.

How can I solve it? Would you please help me? Thank you.