MahApps.Metro怎么调用消息窗口

  public partial class MainWindow : MetroWindow
    {
        public MainWindow()
        {
            InitializeComponent();
 
            MessageExt.Instance.ShowDialog = ShowDialog;            MessageExt.Instance.ShowYesNo = ShowYesNo;
        }
        public async void ShowDialog(string message, string title)
        {
            var mySettings = new MetroDialogSettings()
            {
                AffirmativeButtonText = "关闭",
                ColorScheme = MetroDialogColorScheme.Theme
            };
            MessageDialogResult result = await this.ShowMessageAsync(title, message, MessageDialogStyle.Affirmative, mySettings);
        }
        public async void ShowYesNo(string message, string title,Action action)        
        {            
　　　　　　　var mySettings = new MetroDialogSettings()
            {
                AffirmativeButtonText = "确定",
                NegativeButtonText = "取消",
                ColorScheme = MetroDialogColorScheme.Theme
            };
            MessageDialogResult result = await this.ShowMessageAsync(title, message, MessageDialogStyle.AffirmativeAndNegative, mySettings);
            if (result == MessageDialogResult.Affirmative)
await Task.Factory.StartNew(action);
         } 
 }

    public sealed class MessageExt
    {
        private static readonly MessageExt instance = new MessageExt();
        private MessageExt()
        {
        }

        public static MessageExt Instance
        {
            get
            {
                return instance;
            }
        } 
        /// <summary>
        /// 调用消息窗口的代理事件
        /// </summary>
        public Action<string, string> ShowDialog { get; set; }
        /// <summary>
        /// 调用消息确认窗口的代理事件
        /// </summary>
        public Action<string, string, Action> ShowYesNo { get; set; }
    }

     MessageExt.Instance.ShowDialog("查询", "提示");

     MessageExt.Instance.ShowYesNo("查询", "提示", new Action(() => {
            MessageBox.Show("我来了");
     }));

 private async void ShowMessageDialog(object sender, RoutedEventArgs e)
        {
            // This demo runs on .Net 4.0, but we're using the Microsoft.Bcl.Async package so we have async/await support
            // The package is only used by the demo and not a dependency of the library!
            MetroDialogOptions.ColorScheme = UseAccentForDialogsMenuItem.IsChecked ? MetroDialogColorScheme.Accented : MetroDialogColorScheme.Theme;

            var mySettings = new MetroDialogSettings()
            {
                AffirmativeButtonText = "Hi",  //确定
                NegativeButtonText = "Go away!", //否
                FirstAuxiliaryButtonText = "Cancel",
//第一个自定义按钮， SecondAuxiliaryButtonText为第二个自定义按钮
                ColorScheme = UseAccentForDialogsMenuItem.IsChecked ? MetroDialogColorScheme.Accented : MetroDialogColorScheme.Theme
            };

            MessageDialogResult result = await this.ShowMessageAsync("Hello!", "Welcome to the world of metro!",
                MessageDialogStyle.AffirmativeAndNegativeAndSingleAuxiliary, mySettings);

            if (result != MessageDialogResult.FirstAuxiliary) //这里编写点击后的代码
                await this.ShowMessageAsync("Result", "You said: " + (result == MessageDialogResult.Affirmative ? mySettings.AffirmativeButtonText : mySettings.NegativeButtonText +
                    Environment.NewLine + Environment.NewLine + "This dialog will follow the Use Accent setting."));
        }


        private async void ShowLimitedMessageDialog(object sender, RoutedEventArgs e)
        {
            var mySettings = new MetroDialogSettings()
            {
                AffirmativeButtonText = "Hi",
                NegativeButtonText = "Go away!",
                FirstAuxiliaryButtonText = "Cancel",
                MaximumBodyHeight = 100,
                ColorScheme = UseAccentForDialogsMenuItem.IsChecked ? MetroDialogColorScheme.Accented : MetroDialogColorScheme.Theme
            };

            MessageDialogResult result = await this.ShowMessageAsync("Hello!", "Welcome to the world of metro!" + string.Join(Environment.NewLine, "abc","def","ghi", "jkl","mno","pqr","stu","vwx","yz"),
                MessageDialogStyle.AffirmativeAndNegativeAndSingleAuxiliary, mySettings);

            if (result != MessageDialogResult.FirstAuxiliary)
                await this.ShowMessageAsync("Result", "You said: " + (result == MessageDialogResult.Affirmative ? mySettings.AffirmativeButtonText : mySettings.NegativeButtonText +
                    Environment.NewLine + Environment.NewLine + "This dialog will follow the Use Accent setting."));
        }