mcs/class/System/System.ComponentModel/TypeConverter.cs

   1 //
   2 // System.ComponentModel.TypeConverter.cs
   3 //
   4 // Authors:
   5 //   Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   7 //
   8 // (C) 2002/2003 Ximian, Inc (http://www.ximian.com)
   9 // (C) 2003 Andreas Nahr
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.Globalization;
  15 using System.Runtime.InteropServices;
  16
  17 namespace System.ComponentModel
  18 {
  19         [ComVisible (true)]
  20         public class TypeConverter
  21         {
  22                 public bool CanConvertFrom (Type sourceType)
  23                 {
  24                         return CanConvertFrom (null, sourceType);
  25                 }
  26
  27                 public virtual bool CanConvertFrom (ITypeDescriptorContext context, Type sourceType)
  28                 {
  29                         return false;
  30                 }
  31
  32                 public bool CanConvertTo (Type destinationType)
  33                 {
  34                         return CanConvertTo (null, destinationType);
  35                 }
  36
  37                 public virtual bool CanConvertTo (ITypeDescriptorContext context, Type destinationType)
  38                 {
  39                         return (destinationType == typeof (string));
  40                 }
  41
  42                 public object ConvertFrom (object o)
  43                 {
  44                         return ConvertFrom (null, CultureInfo.CurrentCulture, o);
  45                 }
  46
  47                 public virtual object ConvertFrom (ITypeDescriptorContext context, CultureInfo culture, object value)
  48                 {
  49                         throw new NotSupportedException (this.ToString() + " cannot be created from '" +
  50                                                          value.GetType().ToString() + "'");
  51                 }
  52
  53                 public object ConvertFromInvariantString (string text)
  54                 {
  55                         return ConvertFromInvariantString (null, text);
  56                 }
  57
  58                 public object ConvertFromInvariantString (ITypeDescriptorContext context, string text)
  59                 {
  60                         return ConvertFromString (context, CultureInfo.InvariantCulture, text);
  61                 }
  62
  63                 public object ConvertFromString (string text)
  64                 {
  65                         return ConvertFrom (text);
  66                 }
  67
  68                 public object ConvertFromString (ITypeDescriptorContext context, string text)
  69                 {
  70                         return ConvertFromString (context, CultureInfo.CurrentCulture, text);
  71                 }
  72
  73                 public object ConvertFromString (ITypeDescriptorContext context, CultureInfo culture, string text)
  74                 {
  75                         return ConvertFrom (context, culture, text);
  76                 }
  77
  78                 public object ConvertTo (object value, Type destinationType)
  79                 {
  80                         return ConvertTo (null, null, value, destinationType);
  81                 }
  82
  83                 public virtual object ConvertTo (ITypeDescriptorContext context, CultureInfo culture, object value,
  84                                                  Type destinationType)
  85                 {
  86                         // context? culture?
  87                         if (destinationType == null)
  88                                 throw new ArgumentNullException ("destinationType");
  89
  90                         if (destinationType == typeof (string)) {
  91                                 if (value != null)
  92                                         return value.ToString();
  93                                 return String.Empty;
  94                         }
  95
  96                         throw new NotSupportedException ("Conversion not supported");
  97                 }
  98
  99                 public string ConvertToInvariantString (object value)
 100                 {
 101                         return ConvertToInvariantString (null, value);
 102                 }
 103
 104                 public string ConvertToInvariantString (ITypeDescriptorContext context, object value)
 105                 {
 106                         return (string) ConvertTo (context, CultureInfo.InvariantCulture, value, typeof (string));
 107                 }
 108
 109                 public string ConvertToString (object value)
 110                 {
 111                         return (string) ConvertTo (null, CultureInfo.CurrentCulture, value, typeof (string));
 112                 }
 113
 114                 public string ConvertToString (ITypeDescriptorContext context, object value)
 115                 {
 116                         return (string) ConvertTo (context, CultureInfo.CurrentCulture, value, typeof (string));
 117                 }
 118
 119                 public string ConvertToString (ITypeDescriptorContext context, CultureInfo culture, object value)
 120                 {
 121                         return (string) ConvertTo (context, culture, value, typeof (string));
 122                 }
 123
 124                 protected Exception GetConvertFromException (object value)
 125                 {
 126                         throw new NotSupportedException (this.ToString() + " cannot convert from '" +
 127                                                         value.GetType().ToString() + "'");
 128                 }
 129
 130                 protected Exception GetConvertToException (object value, Type destinationType)
 131                 {
 132                         throw new NotSupportedException (this.ToString() + " cannot convert from '" +
 133                                                         value.GetType().ToString() + "' to '" + destinationType.ToString() + "'");
 134                 }
 135
 136                 public object CreateInstance (IDictionary propertyValues)
 137                 {
 138                         return CreateInstance (null, propertyValues);
 139                 }
 140
 141                 public virtual object CreateInstance (ITypeDescriptorContext context, IDictionary propertyValues)
 142                 {
 143                         return null;
 144                 }
 145
 146                 public bool GetCreateInstanceSupported ()
 147                 {
 148                         return GetCreateInstanceSupported (null);
 149                 }
 150
 151                 public virtual bool GetCreateInstanceSupported (ITypeDescriptorContext context)
 152                 {
 153                         return false;
 154                 }
 155
 156                 public PropertyDescriptorCollection GetProperties (object value)
 157                 {
 158                         return GetProperties (null, value);
 159                 }
 160
 161                 public PropertyDescriptorCollection GetProperties (ITypeDescriptorContext context, object value)
 162                 {
 163                         return GetProperties (context, value, null);
 164                 }
 165
 166                 public virtual PropertyDescriptorCollection GetProperties (ITypeDescriptorContext context,
 167                                                                            object value, Attribute[] attributes)
 168                 {
 169                         return null;
 170                 }
 171
 172                 public bool GetPropertiesSupported ()
 173                 {
 174                         return GetPropertiesSupported (null);
 175                 }
 176
 177                 public virtual bool GetPropertiesSupported (ITypeDescriptorContext context)
 178                 {
 179                         return false;
 180                 }
 181
 182                 public ICollection GetStandardValues ()
 183                 {
 184                         return GetStandardValues (null);
 185                 }
 186
 187                 public virtual StandardValuesCollection GetStandardValues (ITypeDescriptorContext context)
 188                 {
 189                         return null;
 190                 }
 191
 192                 public bool GetStandardValuesExclusive ()
 193                 {
 194                         return GetStandardValuesExclusive (null);
 195                 }
 196
 197                 public virtual bool GetStandardValuesExclusive (ITypeDescriptorContext context)
 198                 {
 199                         return false;
 200                 }
 201
 202                 public bool GetStandardValuesSupported ()
 203                 {
 204                         return GetStandardValuesSupported (null);
 205                 }
 206
 207                 public virtual bool GetStandardValuesSupported (ITypeDescriptorContext context)
 208                 {
 209                         return false;
 210                 }
 211
 212                 public bool IsValid (object value)
 213                 {
 214                         return IsValid (null, value);
 215                 }
 216
 217                 public virtual bool IsValid (ITypeDescriptorContext context, object value)
 218                 {
 219                         return true;
 220                 }
 221
 222                 protected PropertyDescriptorCollection SortProperties (PropertyDescriptorCollection props, string[] names)
 223                 {
 224                         props.Sort (names);
 225                         return props;
 226                 }
 227
 228                 public class StandardValuesCollection : ICollection, IEnumerable
 229                 {
 230                         private ICollection values;
 231
 232                         public StandardValuesCollection (ICollection values)
 233                         {
 234                                 this.values = values;
 235                         }
 236
 237                         public void CopyTo (Array array, int index)
 238                         {
 239                                 values.CopyTo (array, index);
 240                         }
 241
 242                         public IEnumerator GetEnumerator ()
 243                         {
 244                                 return values.GetEnumerator ();
 245                         }
 246
 247                         bool ICollection.IsSynchronized {
 248                                 get { return false; }
 249                         }
 250
 251                         object ICollection.SyncRoot {
 252                                 get { return null; }
 253                         }
 254
 255                         int ICollection.Count {
 256                                 get { return this.Count; }
 257                         }
 258
 259                         public int Count {
 260                                 get { return values.Count; }
 261                         }
 262
 263                         public object this [int index] {
 264                                 get { return ((IList) values) [index]; }
 265                         }
 266                 }
 267
 268                 protected abstract class SimplePropertyDescriptor : PropertyDescriptor
 269                 {
 270                         private Type componentType;
 271                         private Type propertyType;
 272
 273                         public SimplePropertyDescriptor (Type componentType,
 274                                                          string name,
 275                                                          Type propertyType) :
 276                                 this (componentType, name, propertyType, null)
 277                         {
 278                         }
 279
 280                         public SimplePropertyDescriptor (Type componentType,
 281                                                          string name,
 282                                                          Type propertyType,
 283                                                          Attribute [] attributes) : base (name, attributes)
 284                         {
 285                                 this.componentType = componentType;
 286                                 this.propertyType = propertyType;
 287                         }
 288
 289                         public override Type ComponentType {
 290                                 get { return componentType; }
 291                         }
 292
 293                         public override Type PropertyType {
 294                                 get { return propertyType; }
 295                         }
 296
 297                         public override bool IsReadOnly {
 298                                 get { return Attributes.Contains (ReadOnlyAttribute.Yes); }
 299                         }
 300
 301                         public override bool ShouldSerializeValue (object component)
 302                         {
 303                                         return false;
 304                         }
 305
 306                         public override bool CanResetValue (object component)
 307                         {
 308                                 DefaultValueAttribute Attrib = ((DefaultValueAttribute) Attributes[typeof (DefaultValueAttribute)]);
 309                                 if (Attrib == null) {
 310                                         return false;
 311                                 }
 312                                 return (Attrib.Value == GetValue (component));
 313                         }
 314
 315                         public override void ResetValue (object component)
 316                         {
 317                                 DefaultValueAttribute Attrib = ((DefaultValueAttribute) Attributes[typeof (DefaultValueAttribute)]);
 318                                 if (Attrib != null) {
 319                                         SetValue (component, Attrib.Value);
 320                                 }
 321
 322                         }
 323                 }
 324         }
 325 }
 326