如何在WPF多行控件中通过绑定实现文本着色？

针对你的需求，完全可以基于MVVM绑定实现，不需要直接操作RichTextBox或Run元素。下面是两种实用方案，都符合数据驱动的绑定要求：

方案1：使用DataTrigger快速切换样式（适合样式差异较小的场景） #

这种方式最简洁，通过Style的DataTrigger根据MessageType枚举动态调整控件样式，无需额外编写选择器类。

第一步：定义数据模型和ViewModel #

首先确保你的日志模型实现INotifyPropertyChanged，支持动态更新UI：

public enum MessageType
{
    Info,
    Warning,
    Error
}

public class LogMessage : INotifyPropertyChanged
{
    private string _content;
    private MessageType _type;
    private DateTime _timestamp;

    public string Content
    {
        get => _content;
        set { _content = value; OnPropertyChanged(); }
    }

    public MessageType Type
    {
        get => _type;
        set { _type = value; OnPropertyChanged(); }
    }

    public DateTime Timestamp
    {
        get => _timestamp;
        set { _timestamp = value; OnPropertyChanged(); }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public class LogViewModel : INotifyPropertyChanged
{
    public ObservableCollection<LogMessage> LogMessages { get; }

    public LogViewModel()
    {
        LogMessages = new ObservableCollection<LogMessage>();
        // 测试数据
        LogMessages.Add(new LogMessage { Content = "应用初始化完成", Type = MessageType.Info, Timestamp = DateTime.Now });
        LogMessages.Add(new LogMessage { Content = "缓存目录空间不足", Type = MessageType.Warning, Timestamp = DateTime.Now });
        LogMessages.Add(new LogMessage { Content = "数据库连接超时", Type = MessageType.Error, Timestamp = DateTime.Now });
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

第二步：XAML绑定与样式配置 #

用ItemsControl绑定日志集合，通过DataTrigger区分不同消息类型的样式：

<Window x:Class="WpfLogDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfLogDemo"
        Title="日志查看器" Height="450" Width="800">
    <Window.DataContext>
        <local:LogViewModel />
    </Window.DataContext>
    <Grid>
        <ItemsControl ItemsSource="{Binding LogMessages}">
            <!-- 自定义Item模板，包含时间戳和消息内容 -->
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Grid Margin="3">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto" />
                            <ColumnDefinition Width="*" />
                        </Grid.ColumnDefinitions>
                        <TextBlock Text="{Binding Timestamp, StringFormat='[{HH:mm:ss}]'}" 
                                   Margin="0 0 12 0" 
                                   FontWeight="SemiBold"/>
                        <TextBlock Grid.Column="1" 
                                   Text="{Binding Content}">
                            <TextBlock.Style>
                                <Style TargetType="TextBlock">
                                    <!-- 默认样式：信息类消息 -->
                                    <Setter Property="Foreground" Value="#2E7D32"/>
                                    <!-- 根据MessageType切换样式 -->
                                    <Style.Triggers>
                                        <DataTrigger Binding="{Binding Type}" Value="{x:Static local:MessageType.Warning}">
                                            <Setter Property="Foreground" Value="#F57C00"/>
                                            <Setter Property="FontWeight" Value="DemiBold"/>
                                        </DataTrigger>
                                        <DataTrigger Binding="{Binding Type}" Value="{x:Static local:MessageType.Error}">
                                            <Setter Property="Foreground" Value="#D32F2F"/>
                                            <Setter Property="FontWeight" Value="Bold"/>
                                            <Setter Property="TextDecorations" Value="Underline"/>
                                        </DataTrigger>
                                    </Style.Triggers>
                                </Style>
                            </TextBlock.Style>
                        </TextBlock>
                    </Grid>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
            <!-- 添加滚动支持 -->
            <ItemsControl.Template>
                <ControlTemplate TargetType="ItemsControl">
                    <ScrollViewer VerticalScrollBarVisibility="Auto">
                        <ItemsPresenter />
                    </ScrollViewer>
                </ControlTemplate>
            </ItemsControl.Template>
        </ItemsControl>
    </Grid>
</Window>

方案2：使用DataTemplateSelector（适合布局差异较大的场景） #

如果不同类型的日志需要完全不同的布局（比如错误消息要显示图标、警告要加背景色），可以用模板选择器实现更灵活的定制。

第一步：实现模板选择器 #

public class LogMessageTemplateSelector : DataTemplateSelector
{
    public DataTemplate InfoTemplate { get; set; }
    public DataTemplate WarningTemplate { get; set; }
    public DataTemplate ErrorTemplate { get; set; }

    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        if (item is LogMessage logMsg)
        {
            return logMsg.Type switch
            {
                MessageType.Info => InfoTemplate,
                MessageType.Warning => WarningTemplate,
                MessageType.Error => ErrorTemplate,
                _ => base.SelectTemplate(item, container)
            };
        }
        return base.SelectTemplate(item, container);
    }
}

第二步：XAML中定义模板和选择器 #

<Window.Resources>
    <!-- 信息类日志模板 -->
    <DataTemplate x:Key="InfoTemplate">
        <Grid Margin="3">
            <StackPanel Orientation="Horizontal">
                <materialDesign:PackIcon Kind="Information" Width="16" Height="16" Foreground="#2E7D32" Margin="0 0 8 0"/>
                <TextBlock Text="{Binding Timestamp, StringFormat='[{HH:mm:ss}] '}" Foreground="#2E7D32"/>
                <TextBlock Text="{Binding Content}" Foreground="#2E7D32"/>
            </StackPanel>
        </Grid>
    </DataTemplate>

    <!-- 警告类日志模板 -->
    <DataTemplate x:Key="WarningTemplate">
        <Grid Margin="3" Background="#FFF3E0" Padding="4">
            <StackPanel Orientation="Horizontal">
                <materialDesign:PackIcon Kind="Warning" Width="16" Height="16" Foreground="#F57C00" Margin="0 0 8 0"/>
                <TextBlock Text="{Binding Timestamp, StringFormat='[{HH:mm:ss}] '}" Foreground="#F57C00" FontWeight="Bold"/>
                <TextBlock Text="{Binding Content}" Foreground="#F57C00"/>
            </StackPanel>
        </Grid>
    </DataTemplate>

    <!-- 错误类日志模板 -->
    <DataTemplate x:Key="ErrorTemplate">
        <Grid Margin="3" Background="#FFEBEE" Padding="4">
            <StackPanel Orientation="Horizontal">
                <materialDesign:PackIcon Kind="Error" Width="16" Height="16" Foreground="#D32F2F" Margin="0 0 8 0"/>
                <TextBlock Text="{Binding Timestamp, StringFormat='[{HH:mm:ss}] '}" Foreground="#D32F2F" FontWeight="Bold"/>
                <TextBlock Text="{Binding Content}" Foreground="#D32F2F" FontWeight="Bold"/>
            </StackPanel>
        </Grid>
    </DataTemplate>

    <!-- 模板选择器实例 -->
    <local:LogMessageTemplateSelector x:Key="LogTemplateSelector"
                                      InfoTemplate="{StaticResource InfoTemplate}"
                                      WarningTemplate="{StaticResource WarningTemplate}"
                                      ErrorTemplate="{StaticResource ErrorTemplate}"/>
</Window.Resources>

<!-- 绑定ItemsControl -->
<ItemsControl ItemsSource="{Binding LogMessages}"
              ItemTemplateSelector="{StaticResource LogTemplateSelector}">
    <ItemsControl.Template>
        <ControlTemplate TargetType="ItemsControl">
            <ScrollViewer VerticalScrollBarVisibility="Auto">
                <ItemsPresenter />
            </ScrollViewer>
        </ControlTemplate>
    </ItemsControl.Template>
</ItemsControl>

两种方案都完全基于数据绑定，不需要直接操作UI控件，符合MVVM架构要求。你可以根据日志样式的复杂度选择合适的实现方式。

内容的提问来源于stack exchange，提问作者MBit