如何在generic.xaml文件夹中写控件的样式设置

怎么在generic.xaml文件夹中写控件的样式设置啊
我就是想要设置一下控件的样式，想要把下面这段代码放在generic文件中，但是我找不到这个文件啊  不知道要怎么创建这个文件
<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:Phone.Controls;assembly=Phone.Controls">

    <Style TargetType="local:ScrollableTextBlock" >
        <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMedium}"/>
        <Setter Property="Padding" Value="0"/>
        <Setter Property="Width" Value="200" />
        <Setter Property="Height" Value="70" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="local:ScrollableTextBlock">
                    <ScrollViewer x:Name="ScrollViewer" Foreground="{TemplateBinding Foreground}" 
                                  Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" 
                                  BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                        <StackPanel Orientation="Vertical" x:Name="StackPanel" />
                    </ScrollViewer>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>


------解决方案--------------------


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