docs module: changing language now effects the current culture

resolves https://github.com/abpframework/abp/issues/1217

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml.cs

@@ -1,11 +1,14 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.Extensions.Options;
+using Volo.Abp.AspNetCore.Mvc.Localization;
 using Volo.Abp.AspNetCore.Mvc.UI.RazorPages;
+using Volo.Abp.Localization;
 using Volo.Docs.Documents;
 using Volo.Docs.HtmlConverting;
 using Volo.Docs.Models;
@@ -72,6 +75,11 @@ namespace Volo.Docs.Pages.Documents.Project
         {
             DocumentsUrlPrefix = _options.GetFormattedRoutePrefix();
 
+            if (IsDocumentCultureDifferentThanCurrent())
+            {
+                return ReloadPageWithCulture();
+            }
+
             await SetProjectAsync();
             await SetProjectsAsync();
             await SetVersionAsync();
@@ -94,6 +102,24 @@ namespace Volo.Docs.Pages.Documents.Project
             return Page();
         }
 
+        private bool IsDocumentCultureDifferentThanCurrent()
+        {
+            var currentCulture = CultureInfo.CurrentCulture;
+            CultureInfo newCulture;
+
+            try
+            {
+                newCulture = CultureInfo.GetCultureInfo(LanguageCode);
+
+                return currentCulture.Name != newCulture.Name;
+            }
+            catch (CultureNotFoundException)
+            {
+                return false;
+            }
+
+        }
+
         private bool IsDefaultDocument()
         {
             return DocumentName == Project.DefaultDocumentName;
@@ -120,6 +146,15 @@ namespace Volo.Docs.Pages.Documents.Project
             return LanguageConfig.Languages.Any(l => l.Code == LanguageCode);
         }
 
+        private IActionResult ReloadPageWithCulture()
+        {
+            var languageCodeWithSlashAtTheEnd = string.IsNullOrWhiteSpace(LanguageCode) ? "" : LanguageCode + "/";
+            var returnUrl = "/" + DocumentsUrlPrefix + languageCodeWithSlashAtTheEnd + ProjectName + "/" + Version + "/" +
+                            DocumentName;
+
+            return Redirect("/Abp/Languages/Switch?culture=" + LanguageCode + "&uiCulture=" + LanguageCode + "&returnUrl=" + returnUrl);
+        }
+
         private IActionResult RedirectToDefaultLanguage()
         {
             return RedirectToPage(new