Checkbox lost in textchanged event (filtering )

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C#

XAML

WPF

I have a datagridView and I'm trying to filter some row using Id row , it work fine but the problem is when for example I check the datagridCheckboxColumn and I click in the searchbox ( TextChanged event ) , I lost the items checked

How can I recover the checked items when I'm using the searchbox?

What I have tried:

private void Idtxt_TextChanged(object sender, TextChangedEventArgs e)
        {
            if (Idtxt.Text.ToString().Equals(""))
            {
                DataGrid.ItemsSource = dataModelList; 

            }
           List<DataGridModel> filtered = dataModelList.Where(DataGridModel => DataGridModel.workId.StartsWith(Idtxt.Text)).ToList();
        
            DataGrid.ItemsSource = filtered;