1：在项目中新建文件夹“Resouce”，然后再该文件夹下面新增资源文件“AppString.resx”，如果创建一个AppString.resx副本，把文件名改为对应的语言名称，

    如AppString.en-US.resx。,并且把AppString.resx的访问修饰符改为Public

2:打开AppString.resx的cs文件，查看类的访问修饰符是否Public,如果不是，则改为Public。

3:打开App.xmal文件，添加以下代码，目的是用于其它的页面绑定字符内容的资源文件。

4：然后再其它页面就可以使用这个资源文件了，我这里用了三种语言

5：接下来就是语言切换了，我用的是本地存储的方式来保存用户选择的语言，新建一个类来专门负责读取当前用户选择的语言。

代码如下:
public class Configure
    {
        static System.Globalization.CultureInfo currentCulture;
        public static System.Globalization.CultureInfo CurrentCulture
        {
            get
            {

                if (currentCulture == null)
                {
                    try
                    {
                        System.IO.IsolatedStorage.IsolatedStorageSettings appSetting = System.IO.IsolatedStorage.IsolatedStorageSettings.ApplicationSettings;
                        if (appSetting.Contains("language"))
                        {
                            currentCulture = new System.Globalization.CultureInfo((string)appSetting["language"]);
                        }
                    }
                    catch (Exception e)
                    {
                    }

                }
                if (currentCulture == null)
                {
                    currentCulture = new System.Globalization.CultureInfo("en-us");

                }
                return currentCulture;
            }
            set
            {
                currentCulture = value;
                System.Threading.Thread.CurrentThread.CurrentCulture = currentCulture;
                System.Threading.Thread.CurrentThread.CurrentUICulture = currentCulture;

                try
                {
                    System.IO.IsolatedStorage.IsolatedStorageSettings appSetting = System.IO.IsolatedStorage.IsolatedStorageSettings.ApplicationSettings;
                    if (appSetting.Contains("language"))
                    {
                        appSetting["language"] = currentCulture.Name;
                        appSetting.Save();
                    }
                    else
                    {
                        appSetting.Add("language", currentCulture.Name);
                    }

                }
                catch (Exception e)
                {
                }
            }
        }

    }

一下是“切换”按钮的代码

代码如下:
private void button3_Click(object sender, RoutedEventArgs e)
        {
            Configure.CurrentCulture = new CultureInfo(comboBox1.SelectionBoxItem.ToString());
            //if (Configure.CurrentCulture.Name == "zh-CN")
            //{
            //    Configure.CurrentCulture = new CultureInfo("en-US");
            //}
            //else
            //    Configure.CurrentCulture = new CultureInfo("zh-CN");

        }

6：最后是应用程序启动的代码，也就是读取用户保存的语言。在App.xmal.cs文件里，

代码如下:
private void Application_Startup(object sender, StartupEventArgs e)
        {

            CultureInfo culture = Configure.CurrentCulture;
            Thread.CurrentThread.CurrentUICulture = culture;
            Thread.CurrentThread.CurrentCulture = culture;
            this.RootVisual = new MainPage();
        }

注意：按下切换按钮后要重新登录应用程序才能看到效果，并不是即使切换。