FontFamily：指定图标字体资源文件；（推荐iconfont阿里矢量图标）

示例代码：

    <Style x:Key="MyIconButtonStyle" TargetType="Button">
        <Setter Property="Width" Value="40" />
        <Setter Property="Height" Value="30" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="Button">
                    <Border Name="back" Background="Transparent">
                        <TextBlock HorizontalAlignment="Center"
                                   VerticalAlignment="Center"
                                   FontFamily="./Fonts/#iconfont"
                                   FontSize="{Binding FontSize, RelativeSource={RelativeSource AncestorType=Button, Mode=FindAncestor}}"
                                   Text="{Binding Content, RelativeSource={RelativeSource AncestorType=Button, Mode=FindAncestor}}" />
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="back" Property="Background" Value="#FFFFFF" />
                        </Trigger>
                        <Trigger Property="IsPressed" Value="True">
                            <Setter TargetName="back" Property="Background" Value="#AAAAAA" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>