上篇文章我們就Asp.net MVC權限問題做了一個較為全面的解決方案，這篇我們就多語言問題進行探討。
全球化
在IT行業，具有全球化和本地化特性的計算機軟件，可以適應不同的語言，地區差異和目標市場的業務要求。
如果一個網站的目標來自 世界不同地區的的用戶，這些用戶可能會希望看到自己的語言的網站內容。
達到全球化，我們的應用程序，將滿足以下要求：
(1)它可以用不同的語言顯示信息內容。
(2)自動檢測用戶的瀏覽器的語言。
(3)允許用戶方便的更改系統的默認語言，並且系統記住客戶的選擇。
Culture和UICulture
在傳統的.net程序中，全球化主要依靠Culture和UICulture兩個概念。
Culture 決定了日期，數字和貨幣格式,UICulture決定了ResourceManager加載那種語言的資源文件。
.NET中的每一個線程都有CurrentCulture和的CurrentUICulture對象,他們控制了當前線程的語言問題。
Asp.net MVC遵循相同的概念，以應付全球化的要求。
Culture標識
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BaseController
在我們的示例應用程序中，我們構造一個MVC Controller 的基類BaseController，它將設置執行線程的CurrentCulture和的CurrentUICulture。
該BaseController將檢查客戶端的cookie首選Culture標識，如果不存在，將讀取的瀏覽器中首選語言設置。(滿足需求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類封裝了關於文化設置的基本功能，例如設置當前線程的Culture和UICulture對象等等
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"
}
}
使用資源文件
構造多語言的系統的核心就是所有頁面和類里面的literal不能硬編碼，而是要把他們放到資源文件中，並且針對不同的文化名稱( en-GB)構造不同的資源文件,各個資源文件具有相同名稱的條目，但是條目的具體信息隨語言不同而不同，例如
UI.Resources.resx (無文化設置)中有一條設置為
Name Value
About_AboutLabel About
對應的適應於中文的UI.Resources.zh-CN.resx （命名規范為 XXX.文化名稱.resx)
Name Value
About_AboutLabel 關於
在頁面中應該使用資源文件
<span class="supportingFunctions">
@Html.ActionLink(UI_Resources.About_HelpLabel, "Help", "Home")
@Html.ActionLink(UI_Resources.Tab_About, "About", "Home")
</span>
讓瀏覽器記住客戶的選擇
如何讓瀏覽器記住客戶的選擇？
答案很簡單，在主頁面(其實是模板頁,對應Razor的_layout.cshmtl)上面增加需要的文化的Link,當客戶點擊這些link的時候,將客戶的選擇的文化符合保存到Cookie,然后重新導入該頁面，那樣我們的BaseController就可以正確的加載對應的文化和資源了。
<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>
這樣設計的語言解決方案有以下特點
1)程序有很好的性能，無需在數據庫里面存儲所有的頁面的控件翻譯信息
2)資源文件集中了所有的多語言的信息，不同的語言使用不同的文件，便於維護
3)該設計只針對於系統界面的語言問題，業務數據的語言還是得需要存儲於數據庫正確的語言信息 (NVARCHAR, NTEXT..)
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示例代碼