mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/Base/Core/Internal/PropertyEditing/Editors/NewItemFactoryTypeModelToDisplayNameConverter.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4 namespace System.Activities.Presentation.Internal.PropertyEditing.Editors
   5 {
   6     using System;
   7     using System.Windows.Data;
   8     using System.Globalization;
   9
  10     using System.Activities.Presentation.Internal.PropertyEditing.FromExpression.Framework.PropertyInspector;
  11     using System.Activities.Presentation;
  12
  13     // <summary>
  14     // Converts an instance of NewItemFactoryTypeModel to its appropriate display name.
  15     // One way binding to NewItemFactoryTypeModel's DisplayName property also works, but
  16     // for the sake of having a single place that converts NewItemFactoryTypeModel to
  17     // strings, we expose this internal converter.
  18     // </summary>
  19     internal class NewItemFactoryTypeModelToDisplayNameConverter : IValueConverter
  20     {
  21
  22         private static NewItemFactoryTypeModelToDisplayNameConverter _instance;
  23
  24         // <summary>
  25         // Static instance accessor for all non-XAML related conversion needs
  26         // </summary>
  27         public static NewItemFactoryTypeModelToDisplayNameConverter Instance
  28         {
  29             get {
  30                 if (_instance == null)
  31                 {
  32                     _instance = new NewItemFactoryTypeModelToDisplayNameConverter();
  33                 }
  34
  35                 return _instance;
  36             }
  37         }
  38
  39         // Converts an instance of NewItemFactoryTypeModel to its appropriate display name
  40         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
  41         {
  42
  43             if (typeof(string).IsAssignableFrom(targetType))
  44             {
  45
  46                 NewItemFactoryTypeModel model = value as NewItemFactoryTypeModel;
  47                 if (model != null)
  48                 {
  49                     return model.DisplayName ?? string.Empty;
  50                 }
  51             }
  52
  53             return string.Empty;
  54         }
  55
  56         // This class is only a one-way converter
  57         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
  58         {
  59             throw FxTrace.Exception.AsError(new InvalidOperationException());
  60         }
  61     }
  62 }