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SelectableTextBlock

The SelectableTextBlock is a read-only label for displaying text that your users can select and copy. It behaves like TextBlock but adds built-in support for text selection with mouse or keyboard. It can display multiple lines and provides full control over the font used.

Common properties​

PropertyTypeDescription
TextstringThe text to display.
SelectionStartintThe character index for the start of the current selection.
SelectionEndintThe character index for the end of the current selection.
SelectedTextstringGets the currently selected text (read-only).
SelectionBrushIBrushThe brush used to highlight selected text.
SelectionForegroundBrushIBrushThe brush used for the foreground of selected text.
FontSizedoubleThe size of the font.
FontWeightFontWeightThe weight of the font. Default is normal, options include Bold.
FontStyleFontStyleA style to apply to the lettering. Default is normal, options include Italic.
TextDecorationsTextDecorationCollectionA line decoration to apply to the lettering. Default is none, options include Underline, Strikethrough, Baseline and Overline. To apply more than one at the same time, list the options with spaces between.
TextWrappingTextWrappingControls whether text wraps when it reaches the edge of the control. Options include NoWrap, Wrap, and WrapWithOverflow.
xml:spaceXML attributeSet xml:space="preserve" to direct the XML parser to preserve line breaks and whitespace. Without this attribute, whitespace is stripped by default.

Events​

EventDescription
SelectionChangedRaised when the text selection changes, either by user interaction or programmatically.

Basic example​

This example shows selectable text used as a heading, a single line with a custom selection brush, and a multi-line display with a pre-set selection range.

<StackPanel xmlns="https://github.com/avaloniaui"
            Width="200"
            Margin="20">
  <SelectableTextBlock Margin="0 5" FontSize="18" FontWeight="Bold">Heading</SelectableTextBlock>
  <SelectableTextBlock Margin="0 5" FontStyle="Italic"
                       xml:space="preserve"
                       SelectionBrush="Red">This is a single line.</SelectableTextBlock>
  <SelectableTextBlock Margin="0 5" xml:space="preserve"
                       SelectionStart="3" SelectionEnd="13">This is a multi-line
  display that has
  returns in it.
  The text block
  respects the
  line breaks
  set out in XAML.</SelectableTextBlock>
</StackPanel>
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Selecting text programmatically​

You can control which portion of text is selected by setting the SelectionStart and SelectionEnd properties in your code-behind or view model.

<SelectableTextBlock x:Name="MyTextBlock"
                     Text="Select part of this text programmatically." />
<Button Content="Select words 2-4" Click="OnSelectClicked" />
private void OnSelectClicked(object? sender, RoutedEventArgs e)
{
    MyTextBlock.SelectionStart = 7;
    MyTextBlock.SelectionEnd = 24;
}

You can also select all text by setting SelectionStart to 0 and SelectionEnd to the length of the text.

MyTextBlock.SelectionStart = 0;
MyTextBlock.SelectionEnd = MyTextBlock.Text?.Length ?? 0;

Handling selection changes​

Use the SelectionChanged event to respond when your user selects text. This is useful for displaying the selected text elsewhere or performing actions based on the selection.

<SelectableTextBlock x:Name="SourceText"
                     Text="Try selecting some of this text to see it echoed below."
                     SelectionChanged="OnSelectionChanged" />
<TextBlock x:Name="SelectionEcho" Foreground="Gray" />
private void OnSelectionChanged(object? sender, EventArgs e)
{
    SelectionEcho.Text = $"Selected: \"{SourceText.SelectedText}\"";
}

Customizing selection appearance​

You can customize how selected text looks by setting SelectionBrush and SelectionForegroundBrush.

<SelectableTextBlock Text="Custom selection colors"
                     SelectionBrush="#335599FF"
                     SelectionForegroundBrush="White" />

See also​

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