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

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation.Internal.PropertyEditing.Editors
   6 {
   7     using System.Windows.Data;
   8     using System.Globalization;
   9     using System.Collections.Generic;
  10     using System.Runtime;
  11     using System.Collections;
  12     sealed class FlagStringConverter : IValueConverter
  13     {
  14         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
  15         {
  16             if (value != null)
  17             {
  18                 return value.ToString();
  19             }
  20             else
  21             {
  22                 return string.Empty;
  23             }
  24         }
  25
  26         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
  27         {
  28             Type flagType = parameter as Type;
  29             Fx.Assert(flagType != null && flagType.IsEnum, "TargetType should be enum");
  30             Fx.Assert(Attribute.IsDefined(flagType, typeof(FlagsAttribute)), "FlagType should have flags attribute");
  31
  32             if (value == null)
  33             {
  34                 return Enum.ToObject(flagType, 0);
  35             }
  36
  37             string str = (value as string).ToUpperInvariant();
  38             str = str.Trim();
  39             if (str.Equals(string.Empty) || str.Equals("0"))
  40             {
  41                 return Enum.ToObject(flagType, 0);
  42             }
  43
  44             Dictionary<string, object> flagDictionary = GenerateFlagDictionary(flagType);
  45             int flagsIntValue = 0;
  46             string[] names = str.Split(',');
  47             foreach (string name in names)
  48             {
  49                 string flagName = name.Trim();
  50                 if (flagDictionary.ContainsKey(flagName))
  51                 {
  52                     flagsIntValue |= (int)flagDictionary[flagName];
  53                     flagDictionary.Remove(flagName);
  54                 }
  55                 else
  56                 {
  57                     throw FxTrace.Exception.AsError(new ArgumentException(string.Format(CultureInfo.CurrentUICulture, SR.InvalidFlagName, value, flagType.Name)));
  58                 }
  59             }
  60             return Enum.ToObject(flagType, flagsIntValue);
  61         }
  62
  63         static Dictionary<string, object> GenerateFlagDictionary(Type flagType)
  64         {
  65             Dictionary<string, object> flagDictionary = new Dictionary<string, object>();
  66             string[] flagNames = flagType.GetEnumNames();
  67             Array flagValues = flagType.GetEnumValues();
  68             for (int i = 0; i < flagNames.Length; i++)
  69             {
  70                 flagDictionary.Add(flagNames[i].ToUpperInvariant(), flagValues.GetValue(i));
  71             }
  72             return flagDictionary;
  73         }
  74     }
  75 }