how to highlight searched text in DataGrid Cells on WinUI 3 application. Or how to use RichTextBlock in the Datagrid cell?

Hi @EdgeMac ,

Welcome to Microsoft Q&A!

Using VisualTreeHelper, we can find that the text elements in DataGrid are stored in TextBlock. We can use VisualTreeHelper to read all TextBlocks in DataGrid and highlight the text we want. This example is just a simple demonstration and can only find the first matching text. You need to continue to improve it.

<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
    <TextBox x:Name="searchTextBox" Text="Banner"></TextBox>
    <Button x:Name="myButton" Click="myButton_Click">Click Me</Button>
    <controls:DataGrid x:Name="EmployeeGrid"
                ItemsSource="{x:Bind Persons}"
                AutoGenerateColumns="False">
        <controls:DataGrid.Columns>
            <controls:DataGridTextColumn Header="First Name"
                                            Binding="{Binding FirstName}"/>
            <controls:DataGridTextColumn Header="Last Name"
                                            Binding="{Binding LastName}"/>
            <controls:DataGridTextColumn Header="Position"
                                            Binding="{Binding Position}"/>
            <!--<controls:DataGridTemplateColumn  Header="First Name">
                <controls:DataGridTemplateColumn.CellEditingTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding FirstName}"/>
                    </DataTemplate>
                </controls:DataGridTemplateColumn.CellEditingTemplate>
            </controls:DataGridTemplateColumn>-->
                
        </controls:DataGrid.Columns>
    </controls:DataGrid>

 public sealed partial class MainWindow : Window
{
    public List<Department> Departments { get; set; }
    public List<Person> Persons { get; set; }
    public MainWindow()
    {
        this.InitializeComponent();
        Departments = new List<Department>
        {
            new Department {DepartmentId = 1, DepartmentName = "R&D"},
            new Department {DepartmentId = 2, DepartmentName = "Finance"},
            new Department {DepartmentId = 3, DepartmentName = "IT"}
        };
        Persons = new List<Person>
        {
            new Person
            {
                PersonId = 1, DepartmentId = 3, FirstName = "Ronald", LastName = "Rumple",
                Position = "Network Administrator"
            },
            new Person
            {
                PersonId = 2, DepartmentId = 1, FirstName = "Brett", LastName = "Banner",
                Position = "Software Developer"
            },
            new Person
            {
                PersonId = 3, DepartmentId = 2, FirstName = "Alice", LastName = "Anderson",
                Position = "Accountant"
            }
        };
    }
    private void myButton_Click(object sender, RoutedEventArgs e)
    {
        myButton.Content = "Clicked";
        var searchString= searchTextBox.Text.Trim();
        List<TextBlock> txtBlocklist = new List<TextBlock>();
        FindChildren(txtBlocklist, EmployeeGrid);
        foreach (TextBlock txtBlock in txtBlocklist)
        {
            txtBlock.TextHighlighters.Clear();
            int index = txtBlock.Text.IndexOf(searchString);
            if (index >= 0 )
            {
                TextRange textRange = new TextRange() { StartIndex = index, Length = searchString.Length };
                TextHighlighter highlighter = new TextHighlighter()
                {
                    Background = new SolidColorBrush(Colors.Yellow),
                    Ranges = { textRange }
                };
                //add the highlighter
                txtBlock.TextHighlighters.Add(highlighter);
            }
               
        }
    }
    internal static void FindChildren<T>(List<T> results, DependencyObject startNode) where T : DependencyObject
    {
        int count = VisualTreeHelper.GetChildrenCount(startNode);
        for (int i = 0; i < count; i++)
        {
            DependencyObject current = VisualTreeHelper.GetChild(startNode, i);
            if ((current.GetType()).Equals(typeof(T)) || (current.GetType().GetTypeInfo().IsSubclassOf(typeof(T))))
            {
                T asType = (T)current;
                results.Add(asType);
            }
            FindChildren<T>(results, current);
        }
    }
}
//backing data source in MyViewModel
public class Department
{
    public int DepartmentId { get; set; }
    public string DepartmentName { get; set; }
}
public class Person
{
    public int PersonId { get; set; }
    public int DepartmentId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Position { get; set; }
}   

Thank you.

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