public object Convert(object value, Type targetType, object parameter, string language) {
     if (value != null) {
         var page = (Page)value;
         if (page != null) {
             if (page.Icon == null) {
                 var glyph = (string)page.GetValue(AttachedFontIcon.GlyphProperty);
                 if (!string.IsNullOrWhiteSpace(glyph)) {
                     var familary = (string)page.GetValue(AttachedFontIcon.FontFamilyProperty);
                     //control it's color by theme resource.
                     //var color = (Color)page.GetValue(AttachedFontIcon.ColorProperty);
                     var size = (double)page.GetValue(AttachedFontIcon.FontSizeProperty);
                     var icon = new Windows.UI.Xaml.Controls.FontIcon() {
                         Glyph = glyph,
                         FontFamily = familary.ToFontFamily(),
                         FontSize = size,
                         //Foreground = color.ToBrush()
                     };
                     return icon;
                 }
             } else {
                 var img = new Image();
                 img.Source = page.Icon;
                 return img;
             }
         }
     }
     return null;
 }
 public object Convert(object value, Type targetType, object parameter, string language)
 {
     if (value != null)
     {
         var page = (Page)value;
         if (page != null)
         {
             if (page.Icon == null)
             {
                 var glyph = (string)page.GetValue(AttachedFontIcon.GlyphProperty);
                 if (!string.IsNullOrWhiteSpace(glyph))
                 {
                     var familary = (string)page.GetValue(AttachedFontIcon.FontFamilyProperty);
                     //control it's color by theme resource.
                     //var color = (Color)page.GetValue(AttachedFontIcon.ColorProperty);
                     var size = (double)page.GetValue(AttachedFontIcon.FontSizeProperty);
                     var icon = new Windows.UI.Xaml.Controls.FontIcon()
                     {
                         Glyph      = glyph,
                         FontFamily = familary.ToFontFamily(),
                         FontSize   = size,
                         //Foreground = color.ToBrush()
                     };
                     return(icon);
                 }
             }
             else
             {
                 var img = new Image();
                 img.Source = page.Icon;
                 return(img);
             }
         }
     }
     return(null);
 }