从Datatemplate Triggers后面的代码中获取绑定表达式

我被设置为维护一个wpf应用程序，其中有一个用于日志记录的列表框。

使用列表框显示的项目类型为TextMessage，即列表框通过

绑定到这些文本消息

ObservableCollection<TextMessage> Messages; listBox.DataContext = Messages;

消息然后添加类似

的内容

Messages.Add(new TextMessage("Test", TypeOfMessage.Headline));

这是TextMessage类的定义

public enum TypeOfMessage
{
    Normal,
    Headline,
    Focus,
    Important,
    Fail,
    Success
}
public class TextMessage
{
    public TextMessage(string content, TypeOfMessage typeOfMessage)
    {
        Content = content;
        TypeOfMessage = typeOfMessage;
        CreationTime = DateTime.Now;
    }
    public string Content { get; }
    public TypeOfMessage TypeOfMessage { get; }
    public DateTime CreationTime { get; }
}

列表框的xaml定义如下:

    <ListBox x:Name="listBox" HorizontalAlignment="Left" Height="196" Margin="101,77,0,0" VerticalAlignment="Top" Width="256" ItemsSource="{Binding}" SelectionMode="Multiple">

        <ListBox.InputBindings>
            <KeyBinding
                    Key="C"
                    Modifiers="Control"
                    Command="Copy"
                />
        </ListBox.InputBindings>
        <ListBox.CommandBindings>
            <CommandBinding 
                    Command="Copy"
                    Executed="DoPerformCopy"
                />
        </ListBox.CommandBindings>

        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock x:Name="TextToShow"  Text="{Binding Content}"></TextBlock>
                <DataTemplate.Triggers>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Normal">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="Black"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Focus">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="Black"/>
                        <Setter TargetName="TextToShow" Property="FontWeight" Value="Bold"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Headline">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="RoyalBlue"/>
                        <Setter TargetName="TextToShow" Property="FontWeight" Value="Bold"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Important">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="Red"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Fail">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="Red"/>
                        <Setter TargetName="TextToShow" Property="FontWeight" Value="Bold"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding TypeOfMessage}" Value="Success">
                        <Setter TargetName="TextToShow" Property="Foreground" Value="Green"/>
                        <Setter TargetName="TextToShow" Property="FontWeight" Value="Bold"/>
                    </DataTrigger>
                </DataTemplate.Triggers>
            </DataTemplate>
        </ListBox.ItemTemplate>

    </ListBox>

这工作得很好(即消息显示在列表框中不同的字体粗细和颜色取决于他们的类型)，但现在的问题:

是否有任何方法使用BindingExpression或任何其他方法从xaml定义后面的代码中获得字体格式和着色?

原因是，我只想有格式化在一个地方(只是在xaml，因为它是现在)，但仍然能够重用它，当我想复制的内容(使用后面的代码)，包括字体格式到剪贴板。

的例子:

    private void DoPerformCopy()
    {
        RichTextBox rtb = new RichTextBox();
        foreach (TextMessage message in (listBox as ListBox)?.SelectedItems.Cast<TextMessage>().ToList())
        {
            TextPointer startPos = rtb.CaretPosition;
            rtb.AppendText(message.Content);
            rtb.Selection.Select(startPos, rtb.CaretPosition.DocumentEnd);
            //
            // Here it would be very nice to instead having multiple switch statements to get the formatting for the 
            // TypeOfMessage from the xaml file.
            SolidColorBrush scb = new SolidColorBrush(message.TypeOfMessage == TypeOfMessage.Fail ? Colors.Red);
            //
            rtb.Selection.ApplyPropertyValue(RichTextBox.ForegroundProperty, scb);
        }
        // Now copy the whole thing to the Clipboard
        rtb.Selection.Select(rtb.Document.ContentStart, rtb.Document.ContentEnd);
        rtb.Copy();
    }

由于我是wpf的新手，如果有人有解决这个问题的建议，我将非常感激。(我已经努力在stackoverflow上找到解决方案，但到目前为止我还没有成功)

提前感谢，

国王的问候马格努斯

private void DoPerformCopy(object sender, EventArgs e)
{
    RichTextBox rtb = new RichTextBox();
    foreach (TextMessage message in (listBox as ListBox)?.SelectedItems.Cast<TextMessage>().ToList())
    {
        ContentPresenter cp = new ContentPresenter();
        cp.Content = message;
        cp.ContentTemplate = listBox.ItemTemplate;
        cp.ApplyTemplate();
        var tb = VisualTreeHelper.GetChild(cp, 0) as TextBlock;
        var fg = tb.Foreground;
        var fw = tb.FontWeight;
        var tr = new TextRange(rtb.Document.ContentEnd, rtb.Document.ContentEnd);
        tr.Text = message.Content;
        tr.ApplyPropertyValue(RichTextBox.ForegroundProperty, fg);
        tr.ApplyPropertyValue(RichTextBox.FontWeightProperty, fw);
    }
    // Now copy the whole thing to the Clipboard
    rtb.Selection.Select(rtb.Document.ContentStart, rtb.Document.ContentEnd);
    rtb.Copy();
}