WPF реализация

src/Sms.TaskTwo.Wpf/Converters/StringNotEmptyToVisibilityConverter.cs

@@ -0,0 +1,16 @@
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+
+namespace Sms.TaskTwo.Wpf.Converters;
+
+public sealed class StringNotEmptyToVisibilityConverter : IValueConverter
+{
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture) =>
+        value is string text && !string.IsNullOrEmpty(text)
+            ? Visibility.Visible
+            : Visibility.Collapsed;
+
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture) =>
+        throw new NotSupportedException();
+}