GeekDesk/Resource/DefaultIconfont/MyIcon.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    >

    <Style x:Key="MyIcon" TargetType="TextBlock">
        <Setter Property="FontFamily" Value="/GeekDesk;component/Fonts/#iconfont"></Setter>
        <Setter Property="TextAlignment" Value="Center"/>
        <Setter Property="HorizontalAlignment" Value="Center"/>
        <Setter Property="VerticalAlignment" Value="Center"/>
        <Setter Property="FontSize" Value="20"/>
    </Style>
</ResourceDictionary>