mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/Base/Core/Internal/PropertyEditing/FromExpression/Framework/Data/NullToBoolConverter.cs

   1 // -------------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation. All Rights Reserved.
   3 // -------------------------------------------------------------------
   4 //From \\authoring\Sparkle\Source\1.0.1083.0\Common\Source\Framework\Data
   5 namespace System.Activities.Presentation.Internal.PropertyEditing.FromExpression.Framework.Data
   6 {
   7     using System;
   8     using System.Collections;
   9     using System.ComponentModel;
  10     using System.Diagnostics;
  11     using System.Globalization;
  12     using System.Reflection;
  13     using System.Windows;
  14     using System.Windows.Controls;
  15     using System.Windows.Data;
  16     using System.Diagnostics.CodeAnalysis;
  17     using System.Runtime;
  18
  19     // <summary>
  20     // Converts non-null to true, and null to false.
  21     // </summary>
  22     [SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]
  23     internal class NullToBoolConverter : IValueConverter
  24     {
  25         // IValueConverter Implementation
  26
  27         public object ConvertBack(object o, Type targetType, object parameter, CultureInfo culture)
  28         {
  29             Fx.Assert(false, "NullToBoolConverter can only be used for forward conversion.");
  30             return null;
  31         }
  32
  33         public object Convert(object o, Type targetType, object parameter, CultureInfo culture)
  34         {
  35             return o != null;
  36         }
  37
  38     }
  39 }