private void UserControl_SizeChanged(object sender, SizeChangedEventArgs e) { if (!e.WidthChanged) { return; } if (ResultListBox.ItemsSource == null) { return; } var textWidthManager = new TextWidthManager(); foreach (SearchResult item in ResultListBox.ItemsSource) { var searchBoxInfo = new SearchBoxInfo { Width = e.NewSize.Width, FontSize = ResultListBox.FontSize, FontName = ResultListBox.FontFamily.ToString() }; item.ShowPath = textWidthManager.GetSubStringForWidth(item.FullPath, searchBoxInfo); } }