RichTextBlockOverflow.IsTextTrimmedChanged Event


Occurs when the IsTextTrimmed property value has changed.

Equivalent WinUI event: Microsoft.UI.Xaml.Controls.RichTextBlockOverflow.IsTextTrimmedChanged.

// Register
event_token IsTextTrimmedChanged(TypedEventHandler<RichTextBlockOverflow, IsTextTrimmedChangedEventArgs const&> const& handler) const;

// Revoke with event_token
void IsTextTrimmedChanged(event_token const* cookie) const;

// Revoke with event_revoker
RichTextBlockOverflow::IsTextTrimmedChanged_revoker IsTextTrimmedChanged(auto_revoke_t, TypedEventHandler<RichTextBlockOverflow, IsTextTrimmedChangedEventArgs const&> const& handler) const;
public event TypedEventHandler<RichTextBlockOverflow,IsTextTrimmedChangedEventArgs> IsTextTrimmedChanged;
function onIsTextTrimmedChanged(eventArgs) { /* Your code */ }
richTextBlockOverflow.addEventListener("istexttrimmedchanged", onIsTextTrimmedChanged);
richTextBlockOverflow.removeEventListener("istexttrimmedchanged", onIsTextTrimmedChanged);
- or -
richTextBlockOverflow.onistexttrimmedchanged = onIsTextTrimmedChanged;
Public Custom Event IsTextTrimmedChanged As TypedEventHandler(Of RichTextBlockOverflow, IsTextTrimmedChangedEventArgs) 
<RichTextBlockOverflow IsTextTrimmedChanged="eventhandler"/>

Event Type


Windows requirements

Device family
Windows 10 Fall Creators Update (introduced in 10.0.16299.0)
API contract
Windows.Foundation.UniversalApiContract (introduced in v5.0)


In this example, we construct a three column layout using a RichTextBlock and two RichTextBlockOverflow controls. We set the TextTrimming property of the RichTextBlock to CharacterEllipsis and bind it to the first RichTextBlockOverflow, which is then bound to the second RichTextBlockOverflow.

Resizing the window causes the columns to resize, which triggers the IsTextTrimmedChanged event.

    <Grid x:Name="ColumnGrid" Height="200">
            <ColumnDefinition />
            <ColumnDefinition />
            <ColumnDefinition />
        <RichTextBlock Grid.Column="0" Margin="12,0" 
                        OverflowContentTarget="{x:Bind firstOverflowContainer}"
                        TextAlignment="Justify" TextTrimming="CharacterEllipsis"                         
                Linked text containers allow text which does not fit in one element 
                to overflow into a different element on the page. Creative use of 
                linked text containers enables basic multicolumn support and other 
                advanced page layouts.
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                consectetur mattis felis rhoncus. Nunc eu nunc rhoncus arcu 
                sollicitudin ultrices. In vulputate eros in mauris aliquam id 
                dignissim nisl laoreet.
        <RichTextBlockOverflow x:Name="firstOverflowContainer" Grid.Column="1"  Margin="12,0"
                                OverflowContentTarget="{x:Bind secondOverflowContainer}" />
        <RichTextBlockOverflow x:Name="secondOverflowContainer" Grid.Column="2" Margin="12,0" 
namespace TextTrimming1
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
        public MainPage()

        private void RichTextBlock_IsTextTrimmedChanged(RichTextBlock sender, IsTextTrimmedChangedEventArgs args)
            if (sender.IsTextTrimmed)
                //do something

        private void OverflowContainer_IsTextTrimmedChanged(RichTextBlockOverflow sender, IsTextTrimmedChangedEventArgs args)
            if (sender.IsTextTrimmed)
                ColumnGrid.Height += 100;


If the TextTrimming property of RichTextBlock /@"Windows.UI.Xaml.Controls.TextBlock?text=TextBlock" is set to None (default), no trim indicator is drawn and the IsTextTrimmedChanged event does not fire.

Applies to