应用这种风格到你的文本框，这就是它(灵感来自这篇文章):

<Style x:Key="SelectableTextBlockLikeStyle" TargetType="TextBox" BasedOn="{StaticResource {x:Type TextBox}}">
    <Setter Property="IsReadOnly" Value="True"/>
    <Setter Property="IsTabStop" Value="False"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="Padding" Value="-2,0,0,0"/>
    <!-- The Padding -2,0,0,0 is required because the TextBox
        seems to have an inherent "Padding" of about 2 pixels.
        Without the Padding property,
        the text seems to be 2 pixels to the left
        compared to a TextBlock
    -->
    <Style.Triggers>
        <MultiTrigger>
            <MultiTrigger.Conditions>
                <Condition Property="IsMouseOver" Value="False" />
                <Condition Property="IsFocused" Value="False" />
            </MultiTrigger.Conditions>
            <Setter Property="Template">
                <Setter.Value>
                <ControlTemplate TargetType="{x:Type TextBox}">
                    <TextBlock Text="{TemplateBinding Text}" 
                             FontSize="{TemplateBinding FontSize}"
                             FontStyle="{TemplateBinding FontStyle}"
                             FontFamily="{TemplateBinding FontFamily}"
                             FontWeight="{TemplateBinding FontWeight}"
                             TextWrapping="{TemplateBinding TextWrapping}"
                             Foreground="{DynamicResource NormalText}"
                             Padding="0,0,0,0"
                                       />
                </ControlTemplate>
                </Setter.Value>
            </Setter>
        </MultiTrigger>
    </Style.Triggers>
</Style>

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;
    }
}

TextBlock没有模板。因此，为了实现这一点，我们需要使用一个文本框，其风格被改变为一个文本块的行为。

<Style x:Key="TextBlockUsingTextBoxStyle" BasedOn="{x:Null}" TargetType="{x:Type TextBox}">
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="BorderBrush" Value="{StaticResource TextBoxBorder}"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="Padding" Value="1"/>
    <Setter Property="AllowDrop" Value="true"/>
    <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
    <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
    <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TextBox}">
                <TextBox BorderThickness="{TemplateBinding BorderThickness}" IsReadOnly="True" Text="{TemplateBinding Text}" Background="{x:Null}" BorderBrush="{x:Null}" />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

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
         }
};

我同意大多数答案在这里不创建一个可选的文本块。@Billy Willoughby的工作得很好，但是它没有一个明显的选择线索。我想扩展他的扩展，可以突出显示文本，因为它被选中。它还包含双击和三次点击选择。如果需要，您可以添加带有“Copy”的上下文菜单。 它使用Background属性来“突出显示”所选内容，因此它会覆盖Run。背景

https://github.com/mwagnerEE/WagnerControls

有一个替代的解决方案，可能适用于这篇博客文章中提到的RichTextBox -它使用一个触发器来交换控件模板，当使用悬停在控件上时-应该有助于性能