引用《深入浅出WPF》对资源的解读：

每个WPF的界面元素都具有一个名为Resources的属性，这个属性继承自FrameworkElement类，其类型为ResourceDictionary。ResourceDictionary能够以“键－值”对的形式存储资源，当需要使用某个资源时，使用“键－值”对可以索引到资源对象。
——刘铁猛.深入浅出WPF(Kindle位置2580-2582).中国水利水电出版社.Kindle版本.
一般是定义一个资源文件，然后再应用该文件

    <Window.Resources>
        <ResourcesDictionary Source="x.xaml">
    </Window.Resources>

下面的代码是摘抄自ScreenToGif的StringResources.zh.xaml文件

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:s="clr-namespace:System;assembly=mscorlib"
                    xml:space="preserve">
    
    <!--To use a new line: &#x0d;-->
    <!--Or CarriageReturn + NewLine: &#x0d;&#x0a; or &#10;--> 
    <!--Special texts like {0}, are place holders for dynamic values, such as numbers.-->
    
    <!--General-->
    <s:String x:Key="Ok">确定</s:String>
    <s:String x:Key="Back">返回</s:String>
    <s:String x:Key="Cancel">取消</s:String>
    <s:String x:Key="Yes">是</s:String>
    <s:String x:Key="No">否</s:String>
    <s:String x:Key="Frame">帧</s:String>
    <s:String x:Key="Suppress">隐藏</s:String>
    <s:String x:Key="Preview">预览</s:String>
    <s:String x:Key="S.Add">添加</s:String>
    <s:String x:Key="S.Edit">编辑</s:String>
    <s:String x:Key="S.Id">标识</s:String>
    <s:String x:Key="S.Title">标题</s:String>
    <s:String x:Key="S.Description">描述</s:String>
    <s:String x:Key="S.SelectColor">单击此处选择颜色。</s:String>
</ResourceDictionary>

使用方式（同样摘自ScreenToGif）：

<!--Options-->
<StackPanel Grid.Row="0" Grid.Column="0" Grid.RowSpan="2" x:Name="OptionsStackPanel" Margin="0" MaxWidth="180">
    <n:ImageRadioButton x:Name="AppRadio" Text="{DynamicResource Application}" Content="{StaticResource Vector.Application}" TextWrapping="WrapWithOverflow" IsChecked="True"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="InterfaceRadio" Text="{DynamicResource Interface}" Content="{StaticResource Vector.Colors}" TextWrapping="WrapWithOverflow"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="AutomaticRadio" Text="{DynamicResource S.AutoTasks}" Content="{StaticResource Vector.Encoder}" TextWrapping="WrapWithOverflow"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="ShortcutsRadio" Text="{DynamicResource S.Shortcuts}" Content="{StaticResource Vector.Keyboard}" TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="LanguageRadio" Text="{DynamicResource Language}" Content="{StaticResource Vector.Translate}"  TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="TempRadio" Text="{DynamicResource TemporaryFiles}" Content="{StaticResource Vector.Temporary}" TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="CloudRadioButton" Text="{DynamicResource Clouds}" Content="{StaticResource Vector.Web}" TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="ExtrasRadioButton" Text="{DynamicResource Extras}" Content="{StaticResource Vector.Extras}" TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="DonateRadio" Text="{DynamicResource Donate}" Content="{StaticResource Vector.Money}" TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
    <n:ImageRadioButton x:Name="AboutRadio" Text="{DynamicResource About}" Content="{StaticResource Vector.Info}"  TextWrapping="Wrap"
                        Padding="1,3,5,3" FontSize="17" FontFamily="Segoe UI Semilight" Cursor="Hand" MaxSize="24" HorizontalContentAlignment="Left"/>
</StackPanel>