[ASP.NET] MasterPage套用多語系

說明：一般ASP.NET網頁都是override InitializeCulture method來轉換語系，但因MasterPage是繼承MasterPage class(UserControl)，無提供InitializeCulture method。

作法：
1. 自訂一BasePage class(放於App_Code)並繼承Page class，在BasePage中override InitializeCulture method，再使各page從繼承Page改為namespace.BasePage，例：
BasePage.cs
namespace Web
{
    public class BasePage : Page
    {
        protected override void InitializeCulture()
        {
            string culture = Session["culture"].ToString();
            Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(culture);
            Thread.CurrentThread.CurrentUICulture = new CultureInfo(culture);
            base.InitializeCulture();
        }
    }
}

再搭配如DropDownList等控制項供選擇，例：
xxx.aspx
 <asp:DropDownList ID="ddlLanguage" runat="server" AutoPostBack="True" onselectedindexchanged="ddlLanguage_SelectedIndexChanged">
    <asp:ListItem Value="zh-TW" Text="<%$ Resources:PageResource, LanguageZh %>"></asp:ListItem>
    <asp:ListItem Value="en-US" Text="<%$ Resources:PageResource, LanguageEn %>"></asp:ListItem></asp:DropDownList>

xxx.aspx.cs
protected void ddlLanguage_SelectedIndexChanged(object sender, EventArgs e)
{
        if (this.ddlLanguage.SelectedIndex > 0)
        {
            Session["culture"] = this.ddlLanguage.SelectedValue;
            //reload request page
            Server.Transfer(Request.Path);
        }
}

參考資料：
http://stackoverflow.com/questions/11805897/masterpage-initializeculture-no-suitable-method-found-to-override-error

2. 透過global.asax。