更新

ShrlAlgoToolkit.Mvvm/Converters/NotNullToVisibilityConverter.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using System.Windows;
+using System.Windows.Data;
+
+namespace ShrlAlgoToolkit.Mvvm.Converters
+{
+    /// <summary>
+    /// Converts null or not null to a <see cref="Visibility" />.
+    /// </summary>
+    public class NotNullToVisibilityConverter : IValueConverter
+    {
+        /// <summary>
+        /// The visibility value if the argument is null.
+        /// </summary>
+        public Visibility NullValue { get; set; }
+
+        /// <summary>
+        /// Creates a new <see cref="NotNullToVisibilityConverter" />.
+        /// </summary>
+        public NotNullToVisibilityConverter()
+        {
+            NullValue = Visibility.Collapsed;
+        }
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return value == null ? NullValue : Visibility.Visible;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return Binding.DoNothing;
+        }
+    }
+}