mcs/class/referencesource/System.Activities.Core.Presentation/System/Activities/Core/Presentation/NotConverter.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Core.Presentation
   6 {
   7     // Code borrowed from System.Activities.Presentation
   8
   9     using System;
  10     using System.ComponentModel;
  11     using System.Windows;
  12     using System.Windows.Data;
  13     using System.Globalization;
  14     using System.Reflection;
  15     using System.Diagnostics.CodeAnalysis;
  16
  17     // <summary>
  18     // Transform bool value using logical not.
  19     // </summary>
  20     [SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]
  21     internal sealed class NotConverter : IValueConverter
  22     {
  23         // IValueConverter Members
  24
  25         public object Convert(object o, Type targetType, object parameter, CultureInfo culture)
  26         {
  27             return !(bool)o;
  28         }
  29
  30         public object ConvertBack(object o, Type targetType, object parameter, CultureInfo culture)
  31         {
  32             return !AssureBool(o, false);
  33         }
  34
  35         static bool AssureBool(object value, bool defaultIfNull)
  36         {
  37             if (value is bool?)
  38             {
  39                 bool? nbValue = (bool?)value;
  40
  41                 if (nbValue.HasValue)
  42                 {
  43                     return nbValue.Value;
  44                 }
  45                 else
  46                 {
  47                     return defaultIfNull;
  48                 }
  49             }
  50
  51             return (bool)value;
  52         }
  53     }
  54 }