public FontKey(string fontFamily, float fontSize, Windows.UI.Text.FontWeight fontWeight, Windows.UI.Text.FontStyle fontStyle)
 {
     this.FontFamily = fontFamily;
     this.FontSize   = fontSize;
     this.FontWeight = fontWeight;
     this.FontStyle  = fontStyle;
 }
 public void SetFontStyle(Windows.UI.Text.FontStyle style)
 {
     SubtitleText.FontStyle = style;
 }