mcs/class/System/System.ComponentModel/EnumConverter.cs

   1 //
   2 // System.ComponentModel.EnumConverter.cs
   3 //
   4 // Authors:
   5 //   Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   7 //   Ivan N. Zlatev (contact@i-nz.net)
   8 //
   9 // (C) 2002 Ximian, Inc (http://www.ximian.com)
  10 // (C) 2003 Andreas Nahr
  11 // (C) 2007 Ivan N. Zlatev
  12 //
  13
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34 using System;
  35 using System.Collections;
  36 using System.Globalization;
  37 using System.Reflection;
  38 using System.ComponentModel.Design.Serialization;
  39
  40 namespace System.ComponentModel
  41 {
  42         public class EnumConverter : TypeConverter
  43         {
  44                 private Type type;
  45                 private StandardValuesCollection stdValues;
  46
  47                 public EnumConverter (Type type)
  48                 {
  49                         this.type = type;
  50                 }
  51
  52                 public override bool CanConvertTo (ITypeDescriptorContext context, Type destinationType)
  53                 {
  54                         if (destinationType == typeof (InstanceDescriptor))
  55                                 return true;
  56
  57 #if NET_2_0
  58                         if (destinationType == typeof (Enum[]))
  59                                 return true;
  60 #endif
  61
  62                         return base.CanConvertTo (context, destinationType);
  63                 }
  64
  65                 public override object ConvertTo (ITypeDescriptorContext context,
  66                                                   CultureInfo culture,
  67                                                   object value,
  68                                                   Type destinationType)
  69                 {
  70                         if (destinationType == typeof (string) && value != null) {
  71                                 // we need to be able to convert enum names,
  72                                 // integral values and other enum fields
  73                                 if (value is IConvertible) {
  74                                         Type underlyingType = Enum.GetUnderlyingType (type);
  75                                         if (underlyingType != value.GetType ()) {
  76                                                 value = ((IConvertible) value).ToType (
  77                                                         underlyingType, culture);
  78                                         }
  79                                 }
  80
  81                                 if (!IsFlags && !IsValid (context, value))
  82                                         throw CreateValueNotValidException (value);
  83
  84                                 return Enum.Format (type, value, "G");
  85                         } else if (destinationType == typeof (InstanceDescriptor) && value != null) {
  86                                 string enumString = ConvertToString (context, culture, value);
  87                                 if (IsFlags && enumString.IndexOf (",") != -1) {
  88                                         if (value is IConvertible) {
  89                                                 Type underlyingType = Enum.GetUnderlyingType (type);
  90                                                 object enumValue = ((IConvertible)value).ToType (underlyingType, culture);
  91                                                 MethodInfo toObjectMethod = typeof (Enum).GetMethod ("ToObject", new Type[] { typeof (Type),
  92                                                                                                                                                           underlyingType });
  93                                                 return new InstanceDescriptor (toObjectMethod, new object[] { type, enumValue });
  94                                         }
  95                                 } else {
  96                                         FieldInfo f = type.GetField (enumString);
  97                                         if (f != null)
  98                                                 return new InstanceDescriptor (f, null);
  99                                 }
 100 #if NET_2_0
 101                         } else if (destinationType == typeof (Enum[]) && value != null) {
 102                                 if (!IsFlags) {
 103                                         return new Enum[] { (Enum) Enum.ToObject (type, value) };
 104                                 } else {
 105                                         long valueLong = Convert.ToInt64 (
 106                                                 (Enum) value, culture);
 107                                         Array enumValArray = Enum.GetValues (type);
 108                                         long[] enumValues = new long[enumValArray.Length];
 109                                         for (int i=0; i < enumValArray.Length; i++)
 110                                                 enumValues[i] = Convert.ToInt64 (enumValArray.GetValue (i));
 111
 112                                         ArrayList enums = new ArrayList ();
 113                                         bool interrupt = false;
 114                                         while (!interrupt) {
 115                                                 // interrupt the loop unless we find a match to avoid
 116                                                 // looping indefinitely
 117                                                 interrupt = true;
 118                                                 foreach (long val in enumValues) {
 119                                                         if ((val != 0 && ((val & valueLong) == val)) || val == valueLong) {
 120                                                                 enums.Add (Enum.ToObject (type, val));
 121                                                                 valueLong &= (~val);
 122                                                                 interrupt = false;
 123                                                         }
 124                                                 }
 125                                                 if (valueLong == 0) // nothing left to do
 126                                                         interrupt = true;
 127                                         }
 128
 129                                         // add item for remainder
 130                                         if (valueLong != 0)
 131                                                 enums.Add (Enum.ToObject (type, valueLong));
 132
 133                                         return enums.ToArray (typeof(Enum));
 134                                 }
 135 #endif
 136                         }
 137
 138                         return base.ConvertTo (context, culture, value, destinationType);
 139                 }
 140
 141                 public override bool CanConvertFrom (ITypeDescriptorContext context, Type sourceType)
 142                 {
 143                         if (sourceType == typeof (string))
 144                                 return true;
 145
 146 #if NET_2_0
 147                         if (sourceType == typeof (Enum[]))
 148                                 return true;
 149 #endif
 150
 151                         return base.CanConvertFrom (context, sourceType);
 152                 }
 153
 154                 public override object ConvertFrom (ITypeDescriptorContext context,
 155                                                     CultureInfo culture,
 156                                                     object value)
 157                 {
 158                         if (value is string) {
 159                                 string name = value as string;
 160 #if NET_2_0
 161                                 try {
 162 #endif
 163                                         if (name.IndexOf (',') == -1)
 164                                                 return Enum.Parse (type, name, true);
 165
 166                                         long val = 0;
 167                                         string [] names = name.Split (',');
 168                                         foreach (string n in names) {
 169                                                 Enum e = (Enum) Enum.Parse (type, n, true);
 170                                                 val |= Convert.ToInt64 (e, culture);
 171                                         }
 172                                         return Enum.ToObject (type, val);
 173 #if NET_2_0
 174                                 } catch (Exception ex) {
 175                                         throw new FormatException (name + " is " +
 176                                                 "not a valid value for " +
 177                                                 type.Name, ex);
 178                                 }
 179 #endif
 180 #if NET_2_0
 181                         } else if (value is Enum[]) {
 182                                 long val = 0;
 183                                 foreach (Enum e in (Enum[])value)
 184                                         val |= Convert.ToInt64 (e, culture);
 185                                 return Enum.ToObject (type, val);
 186 #endif
 187                         }
 188
 189                         return base.ConvertFrom (context, culture, value);
 190                 }
 191
 192                 public override bool IsValid (ITypeDescriptorContext context, object value)
 193                 {
 194                         return Enum.IsDefined (type, value);
 195                 }
 196
 197                 public override bool GetStandardValuesSupported (ITypeDescriptorContext context)
 198                 {
 199                         return true;
 200                 }
 201
 202                 public override bool GetStandardValuesExclusive (ITypeDescriptorContext context)
 203                 {
 204                         return !IsFlags;
 205                 }
 206
 207                 public override StandardValuesCollection GetStandardValues (ITypeDescriptorContext context)
 208                 {
 209                         if (stdValues == null) {
 210                                 Array values = Enum.GetValues (type);
 211                                 Array.Sort (values);
 212                                 stdValues = new StandardValuesCollection (values);
 213                         }
 214                         return stdValues;
 215                 }
 216
 217                 protected virtual IComparer Comparer {
 218                         get { return new EnumConverter.EnumComparer (); }
 219                 }
 220
 221                 protected Type EnumType {
 222                         get { return type; }
 223                 }
 224
 225                 protected TypeConverter.StandardValuesCollection Values {
 226                         get { return stdValues;  }
 227                         set { stdValues = value; }
 228                 }
 229
 230                 ArgumentException CreateValueNotValidException (object value)
 231                 {
 232                         string msg = string.Format (CultureInfo.InvariantCulture,
 233                                 "The value '{0}' is not a valid value for the " +
 234                                 "enum '{1}'", value, type.Name);
 235                         return new ArgumentException (msg);
 236                 }
 237
 238                 bool IsFlags {
 239                         get {
 240                                 return (type.IsDefined (typeof (FlagsAttribute),
 241                                         false));
 242                         }
 243                 }
 244
 245                 private class EnumComparer : IComparer
 246                 {
 247                         int IComparer.Compare (object compareObject1, object compareObject2)
 248                         {
 249                                 string CompareString1 = (compareObject1 as string);
 250                                 string CompareString2 = (compareObject2 as string);
 251                                 if ((CompareString1 == null) || (CompareString2 == null))
 252                                         return Collections.Comparer.Default.Compare (compareObject1, compareObject2);
 253                                 return CultureInfo.InvariantCulture.CompareInfo.Compare (CompareString1, CompareString2);
 254                         }
 255                 }
 256         }
 257 }