Can not get url with query string when changing culture - cultureinfo

Question

Culture info is not get query string when I change a language from English to German.
Startup.cs
services.Configure<RequestLocalizationOptions>(options =>
{
var supportedCultures = new[]
{
new CultureInfo("de-DE"),
new CultureInfo("en-US"),
};
options.DefaultRequestCulture = new RequestCulture(culture: "de-DE", uiCulture: "de-DE");
options.SupportedCultures = supportedCultures;
options.SupportedUICultures = supportedCultures;
options.RequestCultureProviders = new List<IRequestCultureProvider>
{
new QueryStringRequestCultureProvider(),
new CookieRequestCultureProvider()
};
});
It works properly when there is no query string in url. But I want to return that particular url with full query string. I wrote a method to set culture like this:
[HttpPost]
public IActionResult SetLanguage(string culture, string returnUrl)
{
Response.Cookies.Append(
CookieRequestCultureProvider.DefaultCookieName,
CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture)),
new CookieOptions { Expires = DateTimeOffset.UtcNow.AddYears(1) }
);
return LocalRedirect(returnUrl);
}
_Layout.cshtml
<form id="selectLanguage" asp-controller="Home"
asp-action="SetLanguage" asp-route-returnUrl="#returnUrl"
method="post" class="form-horizontal" role="form">
<select name="culture" onchange="this.form.submit();"
asp-for="#requestCulture.RequestCulture.UICulture.Name"
asp-items="cultureItems">
</select>
</form>
When I'm changing the lang, then it creates a url as shown here:
How can I get full query string like this:

Answer 1

Try change your returnUrl like below :
var returnUrl = string.IsNullOrEmpty(Context.Request.Path) ? "~/" : $"~{Context.Request.Path.Value+Context.Request.QueryString.Value}";

Answer 2

I would suggest following solution since the accepted does not work when you're url contains a pathbase (which is the case for example when you host your service in IIS in with a virtual path):
returnUrl = UriHelper.BuildRelative(Context.Request.PathBase, Context.Request.Path, Context.Request.QueryString)