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上篇文章我们就Asp.net MVC权限问题做了一个较为全面的解决方案，这篇我们就多语言问题进行探讨。

全球化
在IT行业，具有全球化和本地化特性的计算机软件，可以适应不同的语言，地区差异和目标市场的业务要求。

如果一个网站的目标来自 世界不同地区的的用户，这些用户可能会希望看到自己的语言的网站内容。
达到全球化，我们的应用程序，将满足以下要求：

(1)它可以用不同的语言显示信息内容。
(2)自动检测用户的浏览器的语言。

(3)允许用户方便的更改系统的默认语言，并且系统记住客户的选择。

Culture和UICulture

在传统的.net程序中，全球化主要依靠Culture和UICulture两个概念。

Culture 决定了日期，数字和货币格式,UICulture决定了ResourceManager加载那种语言的资源文件。

.NET中的每一个线程都有CurrentCulture和的CurrentUICulture对象,他们控制了当前线程的语言问题。

Asp.net MVC遵循相同的概念，以应付全球化的要求。

Culture标识

文化名称 Culture 标识 语言、区域
zh-CN 0x0804 Chinese - China
en-GB 0x0809 English - United Kingdom
en-US 0x0409 English - United States
fr-FR 0x040C French - France
ja-JP 0x0411 Japanese - Japan

 

 

 

 

 

 

...

 

 

BaseController

在我们的示例应用程序中，我们构造一个MVC Controller 的基类BaseController，它将设置执行线程的CurrentCulture和的CurrentUICulture。

该BaseController将检查客户端的cookie首选Culture标识，如果不存在，将读取的浏览器中首选语言设置。(满足需求2,3)

[HandleError]
    public class BaseController:Controller
    {
        protected override void ExecuteCore()
        {
            string cultureName = null;
            // Attempt to read the culture cookie from Request
            HttpCookie cultureCookie = Request.Cookies["_culture"];
            if (cultureCookie != null)
                cultureName = cultureCookie.Value;
            else
                // obtain it from HTTP header AcceptLanguages
                cultureName = Request.UserLanguages[0];

            // Validate culture name
            //cultureName = CultureHelper.GetImplementedCulture(cultureName);
            CultureHelper.SetCulture(cultureName);

            base.ExecuteCore();
        }

        protected override void OnException(ExceptionContext filterContext)
        {
            base.OnException(filterContext);
        }

    }

CultureHelper
CultureHelper类封装了关于文化设置的基本功能，例如设置当前线程的Culture和UICulture对象等等

public static class CultureHelper
    {
        // Valid cultures
        private static readonly IList<string> _validCultures = new List<string> { "af", "af-ZA", "sq", "sq-AL", "gsw-FR", "am-ET", "ar", "ar-DZ", "ar-BH", "ar-EG", "ar-IQ", "ar-JO", "ar-KW", "ar-LB", "ar-LY", "ar-MA", "ar-OM", "ar-QA", "ar-SA", "ar-SY", "ar-TN", "ar-AE", "ar-YE", "hy", "hy-AM", "as-IN", "az", "az-Cyrl-AZ", "az-Latn-AZ", "ba-RU", "eu", "eu-ES", "be", "be-BY", "bn-BD", "bn-IN", "bs-Cyrl-BA", "bs-Latn-BA", "br-FR", "bg", "bg-BG", "ca", "ca-ES", "zh-HK", "zh-MO", "zh-CN", "zh-Hans", "zh-SG", "zh-TW", "zh-Hant", "co-FR", "hr", "hr-HR", "hr-BA", "cs", "cs-CZ", "da", "da-DK", "prs-AF", "div", "div-MV", "nl", "nl-BE", "nl-NL", "en", "en-AU", "en-BZ", "en-CA", "en-029", "en-IN", "en-IE", "en-JM", "en-MY", "en-NZ", "en-PH", "en-SG", "en-ZA", "en-TT", "en-GB", "en-US", "en-ZW", "et", "et-EE", "fo", "fo-FO", "fil-PH", "fi", "fi-FI", "fr", "fr-BE", "fr-CA", "fr-FR", "fr-LU", "fr-MC", "fr-CH", "fy-NL", "gl", "gl-ES", "ka", "ka-GE", "de", "de-AT", "de-DE", "de-LI", "de-LU", "de-CH", "el", "el-GR", "kl-GL", "gu", "gu-IN", "ha-Latn-NG", "he", "he-IL", "hi", "hi-IN", "hu", "hu-HU", "is", "is-IS", "ig-NG", "id", "id-ID", "iu-Latn-CA", "iu-Cans-CA", "ga-IE", "xh-ZA", "zu-ZA", "it", "it-IT", "it-CH", "ja", "ja-JP", "kn", "kn-IN", "kk", "kk-KZ", "km-KH", "qut-GT", "rw-RW", "sw", "sw-KE", "kok", "kok-IN", "ko", "ko-KR", "ky", "ky-KG", "lo-LA", "lv", "lv-LV", "lt", "lt-LT", "wee-DE", "lb-LU", "mk", "mk-MK", "ms", "ms-BN", "ms-MY", "ml-IN", "mt-MT", "mi-NZ", "arn-CL", "mr", "mr-IN", "moh-CA", "mn", "mn-MN", "mn-Mong-CN", "ne-NP", "no", "nb-NO", "nn-NO", "oc-FR", "or-IN", "ps-AF", "fa", "fa-IR", "pl", "pl-PL", "pt", "pt-BR", "pt-PT", "pa", "pa-IN", "quz-BO", "quz-EC", "quz-PE", "ro", "ro-RO", "rm-CH", "ru", "ru-RU", "smn-FI", "smj-NO", "smj-SE", "se-FI", "se-NO", "se-SE", "sms-FI", "sma-NO", "sma-SE", "sa", "sa-IN", "sr", "sr-Cyrl-BA", "sr-Cyrl-SP", "sr-Latn-BA", "sr-Latn-SP", "nso-ZA", "tn-ZA", "si-LK", "sk", "sk-SK", "sl", "sl-SI", "es", "es-AR", "es-BO", "es-CL", "es-CO", "es-CR", "es-DO", "es-EC", "es-SV", "es-GT", "es-HN", "es-MX", "es-NI", "es-PA", "es-PY", "es-PE", "es-PR", "es-ES", "es-US", "es-UY", "es-VE", "sv", "sv-FI", "sv-SE", "syr", "syr-SY", "tg-Cyrl-TJ", "tzm-Latn-DZ", "ta", "ta-IN", "tt", "tt-RU", "te", "te-IN", "th", "th-TH", "bo-CN", "tr", "tr-TR", "tk-TM", "ug-CN", "uk", "uk-UA", "wen-DE", "ur", "ur-PK", "uz", "uz-Cyrl-UZ", "uz-Latn-UZ", "vi", "vi-VN", "cy-GB", "wo-SN", "sah-RU", "ii-CN", "yo-NG" };

        // Include ONLY cultures you are implementing
        private static readonly IList<string> _cultures = new List<string> {
            "en-US",  // first culture is the DEFAULT
            "zh-CN"           
        };

         /// <summary>
        /// Returns a valid culture name based on "name" parameter. If "name" is not valid, it returns the default culture "en-US"
        /// </summary>
        /// <param name="name">Culture's name (e.g. en-US)</param>
        public static string GetImplementedCulture(string name)
        {
            // make sure it's not null
            if (string.IsNullOrEmpty(name))
                return GetDefaultCulture(); // return Default culture

            // make sure it is a valid culture first
            if (_validCultures.Where(c => c.Equals(name, StringComparison.InvariantCultureIgnoreCase)).Count() == 0)
                return GetDefaultCulture(); // return Default culture if it is invalid


            // if it is implemented, accept it
            if (_cultures.Where(c => c.Equals(name, StringComparison.InvariantCultureIgnoreCase)).Count() > 0)
                return name; // accept it


            // Find a close match. For example, if you have "en-US" defined and the user requests "en-GB", 
            // the function will return closes match that is "en-US" because at least the language is the same (ie English)  
            var n = GetNeutralCulture(name);
            foreach (var c in _cultures)
                if (c.StartsWith(n))
                    return c;

            // else 
            // It is not implemented
            return GetDefaultCulture(); // return Default culture as no match found
        }

        /// <summary>
        /// set current culture based on input name
        /// </summary>
        /// <param name="name">Culture's name (e.g. en-US)</param>
        public static void SetCulture(string name)
        {
            if (string.IsNullOrEmpty(name)) return;
            // Modify current thread's cultures            
            Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo(name);
            Thread.CurrentThread.CurrentUICulture = Thread.CurrentThread.CurrentCulture;
        }

        /// <summary>
        /// Returns default culture name which is the first name decalared (e.g. en-US)
        /// </summary>
        /// <returns></returns>
        public static string GetDefaultCulture()
        {
            return _cultures[0]; // return Default culture

        }

        public static string GetCurrentCulture()
        {
            return Thread.CurrentThread.CurrentCulture.Name;
        }

        public static string GetCurrentNeutralCulture()
        {
            return GetNeutralCulture(Thread.CurrentThread.CurrentCulture.Name);
        }
        
        public static string GetNeutralCulture(string name)
        {
            if (name.Length < 2)
                return name;

            return name.Substring(0, 2); // Read first two chars only. E.g. "en", "es"
        }

    }

使用资源文件

构造多语言的系统的核心就是所有页面和类里面的literal不能硬编码，而是要把他们放到资源文件中，并且针对不同的文化名称( en-GB)构造不同的资源文件,各个资源文件具有相同名称的条目，但是条目的具体信息随语言不同而不同，例如

UI.Resources.resx (无文化设置)中有一条设置为

Name　　　　　　　　Value

About_AboutLabel    About

对应的适应于中文的UI.Resources.zh-CN.resx （命名规范为  XXX.文化名称.resx)

Name　　　　　　　　Value

About_AboutLabel    关于

在页面中应该使用资源文件

 <span class="supportingFunctions">
          @Html.ActionLink(UI_Resources.About_HelpLabel, "Help", "Home")
            @Html.ActionLink(UI_Resources.Tab_About, "About", "Home")                     
 </span>   

让浏览器记住客户的选择

如何让浏览器记住客户的选择？

答案很简单，在主页面(其实是模板页,对应Razor的_layout.cshmtl)上面增加需要的文化的Link,当客户点击这些link的时候,将客户的选择的文化符合保存到Cookie,然后重新导入该页面，那样我们的BaseController就可以正确的加载对应的文化和资源了。

<span class="language">
                   <a href="javascript:void(0);" class="en-GB">@UI_Resources.Lan_English</a>
                   <a href="javascript:void(0);" class="zh-CN">@UI_Resources.Lan_Chinese</a>
                   <a href="javascript:void(0);" class="ja-JP">@UI_Resources.Lan_Japanese</a>
 </span>

<script type="text/javascript">
    function setCookie(c_name, value, exdays) {
        var exdate = new Date();
        exdate.setDate(exdate.getDate() + exdays);
        var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
        document.cookie = c_name + "=" + c_value;
    }

    $(".language a").click(function () {
        setCookie("_culture", $(this).attr("class"), 365);
        window.location.reload();
    });
</script>

这样设计的语言解决方案有以下特点

1)程序有很好的性能，无需在数据库里面存储所有的页面的控件翻译信息

2)资源文件集中了所有的多语言的信息，不同的语言使用不同的文件，便于维护

3)该设计只针对于系统界面的语言问题，业务数据的语言还是得需要存储于数据库正确的语言信息 (NVARCHAR, NTEXT..)

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示例代码