mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/Base/Core/Internal/PropertyEditing/FromExpression/Framework/Data/SwitchConverter.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.Generic;
   9     using System.ComponentModel;
  10     using System.Diagnostics;
  11     using System.Globalization;
  12     using System.Reflection;
  13     using System.Windows;
  14     using System.Windows.Data;
  15     using System.Windows.Markup;
  16     using System.Windows.Media;
  17     using System.Activities.Presentation;
  18
  19     // <summary>
  20     // Transformer which maps from input values to output values, based on a list of SwitchCase children.
  21     // This isn't strictly a C-style 'switch' statement, since cases aren't guaranteed to be unique.
  22     // </summary>
  23     //
  24     [ContentProperty("Cases")]
  25     internal class SwitchConverter : DependencyObject, IValueConverter
  26     {
  27         static readonly DependencyProperty DefaultValueProperty = DependencyProperty.Register("DefaultValue", typeof(object), typeof(SwitchConverter));
  28         private List<SwitchCase> cases;
  29
  30         public SwitchConverter()
  31         {
  32             this.cases = new List<SwitchCase>();
  33         }
  34
  35         public List<SwitchCase> Cases
  36         {
  37             get { return this.cases; }
  38         }
  39
  40         public object DefaultValue
  41         {
  42             get { return this.GetValue(SwitchConverter.DefaultValueProperty); }
  43             set { this.SetValue(SwitchConverter.DefaultValueProperty, value); }
  44         }
  45
  46         // IValueConverter implementation
  47         public object Convert(object o, Type targetType, object parameter, CultureInfo culture)
  48         {
  49             foreach (SwitchCase switchCase in this.Cases)
  50             {
  51                 if (object.Equals(switchCase.In, o))
  52                 {
  53                     return switchCase.Out;
  54                 }
  55             }
  56
  57             return this.DefaultValue;
  58         }
  59
  60         public object ConvertBack(object o, Type targetType, object parameter, CultureInfo culture)
  61         {
  62             throw FxTrace.Exception.AsError(new InvalidOperationException(ExceptionStringTable.SwitchConverterIsOneWay));
  63         }
  64
  65     }
  66
  67     // <summary>
  68     // Represents a mapping from an input value to an output value.
  69     // </summary>
  70     internal class SwitchCase : DependencyObject
  71     {
  72         static readonly DependencyProperty InProperty = DependencyProperty.Register("In", typeof(object), typeof(SwitchCase));
  73         static readonly DependencyProperty OutProperty = DependencyProperty.Register("Out", typeof(object), typeof(SwitchCase));
  74
  75         public SwitchCase()
  76         {
  77         }
  78
  79         // Properties
  80         public object In
  81         {
  82             get { return (object)this.GetValue(InProperty); }
  83             set { this.SetValue(InProperty, value); }
  84         }
  85
  86         public object Out
  87         {
  88             get { return this.GetValue(OutProperty); }
  89             set { this.SetValue(OutProperty, value); }
  90         }
  91     }
  92
  93     // <summary>
  94     // Convenience class for getting at a particular type.  Useful for databinding.
  95     // Used in XAML as: <TypeReference Type="*typeof(Foo)" />
  96     // </summary>
  97     internal sealed class TypeReference : DependencyObject
  98     {
  99         static readonly DependencyProperty TypeProperty = DependencyProperty.Register("Type", typeof(Type), typeof(TypeReference));
 100
 101         public Type Type
 102         {
 103             get { return (Type)this.GetValue(TypeProperty); }
 104             set { this.SetValue(TypeProperty, value); }
 105         }
 106     }
 107 }