public class SummarizeBehavior :
    TextModificationBehavior

Public Class SummarizeBehavior
    Inherits TextModificationBehavior

<dx:ThemedWindow
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
    xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"
    xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm" 
    xmlns:dxai="http://schemas.devexpress.com/winfx/2008/xaml/ai"
    x:Class="AIAssistant.MainWindow"
    Title="MainWindow" Height="800" Width="800">
    <Grid>
        <dxe:TextEdit TextWrapping="Wrap" AcceptsReturn="True" VerticalContentAlignment="Top">
            <dxmvvm:Interaction.Behaviors>
                <dxai:SummarizeBehavior x:Name="Summarize" SummarizationMode = "Extractive"/>
            </dxmvvm:Interaction.Behaviors>
        </dxe:TextEdit>
    </Grid>
</dx:ThemedWindow>