SettingsItem.xaml

<UserControl x:Class="PaperWriting.SettingsItem"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:PaperWriting"
             x:Name="this"
             mc:Ignorable="d" 
             d:DesignHeight="206.145" d:DesignWidth="669.274">

    <UserControl.Resources>
        <local:SettingOptionValueConverter x:Key="content_converter" />
        <DataTemplate x:Key="richtext_tmpl">
            <TextBox Grid.Column="1" Grid.Row="0" AcceptsReturn="True" Text="{Binding Path=SettingItemValue,Mode=TwoWay,ElementName=this}" 
                 VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" />
        </DataTemplate>
        <DataTemplate x:Key="text_tmpl">
            <TextBox Grid.Column="1" Grid.Row="0" AcceptsReturn="False" Text="{Binding Path=SettingItemValue,Mode=TwoWay,ElementName=this}" 
                 VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" />
        </DataTemplate>
        <DataTemplate x:Key="option_tmpl">
            <ComboBox Grid.Column="1" Grid.Row="0" VerticalContentAlignment="Center"
                  ItemsSource="{Binding Path=SettingItemOptions,ElementName=this}"
                  SelectedValue="{Binding Path=SettingItemValue,Mode=TwoWay,ElementName=this,Converter={StaticResource content_converter}}" />
        </DataTemplate>
        <DataTemplate x:Key="check_tmpl">
            <CheckBox Grid.Column="1" Grid.Row="0" VerticalContentAlignment="Center"
                  IsChecked="{Binding Path=SettingItemValue,Mode=TwoWay,ElementName=this}" />
        </DataTemplate>
        <local:SettingItemSelector x:Key="selector" 
                                   TextTmpl="{StaticResource text_tmpl}" 
                                   RichTextTmpl="{StaticResource richtext_tmpl}" 
                                   OptionTmpl="{StaticResource option_tmpl}" 
                                   CheckTmpl="{StaticResource check_tmpl}"/>
    </UserControl.Resources>
    
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="2*" />
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Column="0" Grid.Row="0" FontFamily="微软雅黑" FontSize="14" Margin="8,0" VerticalAlignment="Top" Text="{Binding SettingItemName}" TextWrapping="Wrap" />
        <ContentControl ContentTemplateSelector="{StaticResource selector}" Grid.Column="1" Content="{Binding SettingItemType}" />
        <TextBlock Grid.Column="1" Grid.Row="1" FontFamily="微软雅黑" FontSize="10" Foreground="Gray" Text="{Binding SettingItemTip}" TextWrapping="Wrap" />
    </Grid>
</UserControl>