public MainPage()
{
    this.InitializeComponent();
    ...
    ...
    ...
    //Make Start result text copiable
    TextBlockStatusStart.IsTextSelectionEnabled = true;
}

虽然这个问题确实说“可选择”，但我相信有意的结果是将文本放到剪贴板上。这可以通过添加一个名为复制的上下文菜单和菜单项来轻松而优雅地实现，该菜单项将Textblock Text属性值放在剪贴板中。只是一个想法而已。

我已经实现了SelectableTextBlock在我的开源控件库。你可以这样使用它:

<jc:SelectableTextBlock Text="Some text" />

public MainPage()
{
    this.InitializeComponent();
    ...
    ...
    ...
    //Make Start result text copiable
    TextBlockStatusStart.IsTextSelectionEnabled = true;
}

以下是对我有效的方法。我创建了一个类TextBlockEx，从TextBox派生，并设置为只读，文本包装在构造函数。

public class TextBlockEx : TextBox
{
    public TextBlockEx()
    {
        base.BorderThickness = new Thickness(0);
        IsReadOnly = true;
        TextWrapping = TextWrapping.Wrap;
        //Background = Brushes.Transparent; // Uncomment to get parent's background color
    }
}

Really nice and easy solution, exactly what I wanted !

我带来了一些小改动

public class TextBlockMoo : TextBlock 
{
    public String SelectedText = "";

    public delegate void TextSelectedHandler(string SelectedText);
    public event TextSelectedHandler OnTextSelected;
    protected void RaiseEvent()
    {
        if (OnTextSelected != null){OnTextSelected(SelectedText);}
    }

    TextPointer StartSelectPosition;
    TextPointer EndSelectPosition;
    Brush _saveForeGroundBrush;
    Brush _saveBackGroundBrush;

    TextRange _ntr = null;

    protected override void OnMouseDown(MouseButtonEventArgs e)
    {
        base.OnMouseDown(e);

        if (_ntr!=null) {
            _ntr.ApplyPropertyValue(TextElement.ForegroundProperty, _saveForeGroundBrush);
            _ntr.ApplyPropertyValue(TextElement.BackgroundProperty, _saveBackGroundBrush);
        }

        Point mouseDownPoint = e.GetPosition(this);
        StartSelectPosition = this.GetPositionFromPoint(mouseDownPoint, true);            
    }

    protected override void OnMouseUp(MouseButtonEventArgs e)
    {
        base.OnMouseUp(e);
        Point mouseUpPoint = e.GetPosition(this);
        EndSelectPosition = this.GetPositionFromPoint(mouseUpPoint, true);

        _ntr = new TextRange(StartSelectPosition, EndSelectPosition);

        // keep saved
        _saveForeGroundBrush = (Brush)_ntr.GetPropertyValue(TextElement.ForegroundProperty);
        _saveBackGroundBrush = (Brush)_ntr.GetPropertyValue(TextElement.BackgroundProperty);
        // change style
        _ntr.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.Yellow));
        _ntr.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.DarkBlue));

        SelectedText = _ntr.Text;
    }
}