我不确定你是否可以使一个TextBlock可选，但另一个选择是使用RichTextBox -它就像你建议的TextBox，但支持你想要的格式。

new TextBox
{
   Text = text,
   TextAlignment = TextAlignment.Center,
   TextWrapping = TextWrapping.Wrap,
   IsReadOnly = true,
   Background = Brushes.Transparent,
   BorderThickness = new Thickness()
         {
             Top = 0,
             Bottom = 0,
             Left = 0,
             Right = 0
         }
};

使用带有这些设置的TextBox来使其只读，看起来像一个TextBlock控件。

<TextBox Background="Transparent"
         BorderThickness="0"
         Text="{Binding Text, Mode=OneWay}"
         IsReadOnly="True"
         TextWrapping="Wrap" />

为torvin的代码添加了Selection & SelectionChanged事件

public class SelectableTextBlock : TextBlock
{

    static readonly Type TextEditorType
    = Type.GetType("System.Windows.Documents.TextEditor, PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35");

    static readonly PropertyInfo IsReadOnlyProp
        = TextEditorType.GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);

    static readonly PropertyInfo TextViewProp
        = TextEditorType.GetProperty("TextView", BindingFlags.Instance | BindingFlags.NonPublic);

    static readonly MethodInfo RegisterMethod
        = TextEditorType.GetMethod("RegisterCommandHandlers",
        BindingFlags.Static | BindingFlags.NonPublic, null, new[] { typeof(Type), typeof(bool), typeof(bool), typeof(bool) }, null);

    static readonly Type TextContainerType
        = Type.GetType("System.Windows.Documents.ITextContainer, PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35");
    static readonly PropertyInfo TextContainerTextViewProp
        = TextContainerType.GetProperty("TextView");

    static readonly PropertyInfo TextContainerTextSelectionProp
        = TextContainerType.GetProperty("TextSelection");

    static readonly PropertyInfo TextContainerProp = typeof(TextBlock).GetProperty("TextContainer", BindingFlags.Instance | BindingFlags.NonPublic);

    static void RegisterCommandHandlers(Type controlType, bool acceptsRichContent, bool readOnly, bool registerEventListeners)
    {
        RegisterMethod.Invoke(null, new object[] { controlType, acceptsRichContent, readOnly, registerEventListeners });
    }

    static SelectableTextBlock()
    {
        FocusableProperty.OverrideMetadata(typeof(SelectableTextBlock), new FrameworkPropertyMetadata(true));
        RegisterCommandHandlers(typeof(SelectableTextBlock), true, true, true);

        // remove the focus rectangle around the control
        FocusVisualStyleProperty.OverrideMetadata(typeof(SelectableTextBlock), new FrameworkPropertyMetadata((object)null));
    }

    //private readonly TextEditorWrapper _editor;
    object? textContainer;
    object? editor;
    public TextSelection TextSelection { get; private set; }

    public SelectableTextBlock()
    {
        textContainer = TextContainerProp.GetValue(this);

        editor = Activator.CreateInstance(TextEditorType, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.CreateInstance,
            null, new[] { textContainer, this, false }, null);


        IsReadOnlyProp.SetValue(editor, true);
        TextViewProp.SetValue(editor, TextContainerTextViewProp.GetValue(textContainer));

        TextSelection = (TextSelection)TextContainerTextSelectionProp.GetValue(textContainer);
        TextSelection.Changed += (s, e) => OnSelectionChanged?.Invoke(this, e);
    }

    public event EventHandler OnSelectionChanged;
}

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。

我找不到任何能真正回答这个问题的例子。所有的答案都使用了一个文本框或RichTextbox。我需要一个解决方案，让我使用一个TextBlock，这是我创建的解决方案。

我相信这样做的正确方法是扩展TextBlock类。这是我用来扩展TextBlock类的代码，以允许我选择文本并将其复制到剪贴板。“sdo”是我在WPF中使用的名称空间引用。

WPF使用扩展类:

xmlns:sdo="clr-namespace:iFaceCaseMain"

<sdo:TextBlockMoo x:Name="txtResults" Background="Black" Margin="5,5,5,5" 
      Foreground="GreenYellow" FontSize="14" FontFamily="Courier New"></TextBlockMoo>

扩展类的代码背后:

public partial class TextBlockMoo : TextBlock 
{
    TextPointer StartSelectPosition;
    TextPointer EndSelectPosition;
    public String SelectedText = "";

    public delegate void TextSelectedHandler(string SelectedText);
    public event TextSelectedHandler TextSelected;

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

        TextRange otr = new TextRange(this.ContentStart, this.ContentEnd);
        otr.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.GreenYellow));

        TextRange ntr = new TextRange(StartSelectPosition, EndSelectPosition);
        ntr.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.White));

        SelectedText = ntr.Text;
        if (!(TextSelected == null))
        {
            TextSelected(SelectedText);
        }
    }
}

示例窗口代码:

    public ucExample(IInstanceHost host, ref String WindowTitle, String ApplicationID, String Parameters)
    {
        InitializeComponent();
        /*Used to add selected text to clipboard*/
        this.txtResults.TextSelected += txtResults_TextSelected;
    }

    void txtResults_TextSelected(string SelectedText)
    {
        Clipboard.SetText(SelectedText);
    }