mcs/class/System.Xaml/System.Xaml/XamlType.cs

   1 //
   2 // Copyright (C) 2010 Novell Inc. http://novell.com
   3 //
   4 // Permission is hereby granted, free of charge, to any person obtaining
   5 // a copy of this software and associated documentation files (the
   6 // "Software"), to deal in the Software without restriction, including
   7 // without limitation the rights to use, copy, modify, merge, publish,
   8 // distribute, sublicense, and/or sell copies of the Software, and to
   9 // permit persons to whom the Software is furnished to do so, subject to
  10 // the following conditions:
  11 //
  12 // The above copyright notice and this permission notice shall be
  13 // included in all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  19 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  20 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  21 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  22 //
  23 using System;
  24 using System.Collections;
  25 using System.Collections.Generic;
  26 using System.ComponentModel;
  27 using System.Linq;
  28 using System.Reflection;
  29 using System.Windows.Markup;
  30 using System.Xaml.Schema;
  31
  32 namespace System.Xaml
  33 {
  34         public class XamlType : IEquatable<XamlType>
  35         {
  36                 public XamlType (Type underlyingType, XamlSchemaContext schemaContext)
  37                         : this (underlyingType, schemaContext, null)
  38                 {
  39                 }
  40
  41                 static readonly Type [] predefined_types = {
  42                                 typeof (XData), typeof (Uri), typeof (TimeSpan), typeof (PropertyDefinition), typeof (MemberDefinition), typeof (Reference)
  43                         };
  44
  45                 public XamlType (Type underlyingType, XamlSchemaContext schemaContext, XamlTypeInvoker invoker)
  46                         : this (schemaContext, invoker)
  47                 {
  48                         if (underlyingType == null)
  49                                 throw new ArgumentNullException ("underlyingType");
  50                         type = underlyingType;
  51                         underlying_type = type;
  52
  53                         XamlType xt;
  54                         if (XamlLanguage.InitializingTypes) {
  55                                 Name = type.GetXamlName ();
  56                                 PreferredXamlNamespace = XamlLanguage.Xaml2006Namespace;
  57                         } else if ((xt = XamlLanguage.AllTypes.FirstOrDefault (t => t.UnderlyingType == type)) != null) {
  58                                 Name = xt.Name;
  59                                 PreferredXamlNamespace = XamlLanguage.Xaml2006Namespace;
  60                         } else {
  61                                 Name = type.GetXamlName ();
  62                                 PreferredXamlNamespace = String.Format ("clr-namespace:{0};assembly={1}", type.Namespace, type.Assembly.GetName ().Name);
  63                         }
  64                 }
  65
  66                 public XamlType (string unknownTypeNamespace, string unknownTypeName, IList<XamlType> typeArguments, XamlSchemaContext schemaContext)
  67                         : this (schemaContext, null)
  68                 {
  69                         if (unknownTypeNamespace == null)
  70                                 throw new ArgumentNullException ("unknownTypeNamespace");
  71                         if (unknownTypeName == null)
  72                                 throw new ArgumentNullException ("unknownTypeName");
  73                         if (schemaContext == null)
  74                                 throw new ArgumentNullException ("schemaContext");
  75
  76                         type = typeof (object);
  77                         Name = unknownTypeName;
  78                         PreferredXamlNamespace = unknownTypeNamespace;
  79                         TypeArguments = typeArguments != null && typeArguments.Count == 0 ? null : typeArguments;
  80                         explicit_ns = unknownTypeNamespace;
  81                 }
  82
  83                 protected XamlType (string typeName, IList<XamlType> typeArguments, XamlSchemaContext schemaContext)
  84                         : this (String.Empty, typeName, typeArguments, schemaContext)
  85                 {
  86                 }
  87
  88                 XamlType (XamlSchemaContext schemaContext, XamlTypeInvoker invoker)
  89                 {
  90                         if (schemaContext == null)
  91                                 throw new ArgumentNullException ("schemaContext");
  92                         SchemaContext = schemaContext;
  93                         this.invoker = invoker ?? new XamlTypeInvoker (this);
  94                 }
  95
  96                 Type type, underlying_type;
  97
  98                 string explicit_ns;
  99
 100                 // populated properties
 101                 XamlType base_type;
 102                 XamlTypeInvoker invoker;
 103
 104                 internal EventHandler<XamlSetMarkupExtensionEventArgs> SetMarkupExtensionHandler {
 105                         get { return LookupSetMarkupExtensionHandler (); }
 106                 }
 107
 108                 internal EventHandler<XamlSetTypeConverterEventArgs> SetTypeConverterHandler {
 109                         get { return LookupSetTypeConverterHandler (); }
 110                 }
 111
 112                 public IList<XamlType> AllowedContentTypes {
 113                         get { return LookupAllowedContentTypes (); }
 114                 }
 115
 116                 public XamlType BaseType {
 117                         get { return LookupBaseType (); }
 118                 }
 119
 120                 public bool ConstructionRequiresArguments {
 121                         get { return LookupConstructionRequiresArguments (); }
 122                 }
 123
 124                 public XamlMember ContentProperty {
 125                         get { return LookupContentProperty (); }
 126                 }
 127
 128                 public IList<XamlType> ContentWrappers {
 129                         get { return LookupContentWrappers (); }
 130                 }
 131
 132                 public XamlValueConverter<XamlDeferringLoader> DeferringLoader {
 133                         get { return LookupDeferringLoader (); }
 134                 }
 135
 136                 public XamlTypeInvoker Invoker {
 137                         get { return LookupInvoker (); }
 138                 }
 139
 140                 public bool IsAmbient {
 141                         get { return LookupIsAmbient (); }
 142                 }
 143
 144                 public bool IsArray {
 145                         get { return LookupCollectionKind () == XamlCollectionKind.Array; }
 146                 }
 147
 148                 // it somehow treats array as not a collection...
 149                 public bool IsCollection {
 150                         get { return LookupCollectionKind () == XamlCollectionKind.Collection; }
 151                 }
 152
 153                 public bool IsConstructible {
 154                         get { return LookupIsConstructible (); }
 155                 }
 156
 157                 public bool IsDictionary {
 158                         get { return LookupCollectionKind () == XamlCollectionKind.Dictionary; }
 159                 }
 160
 161                 public bool IsGeneric {
 162                         get { return type.IsGenericType; }
 163                 }
 164
 165                 public bool IsMarkupExtension {
 166                         get { return LookupIsMarkupExtension (); }
 167                 }
 168                 public bool IsNameScope {
 169                         get { return LookupIsNameScope (); }
 170                 }
 171                 public bool IsNameValid {
 172                         get { return XamlLanguage.IsValidXamlName (Name); }
 173                 }
 174
 175                 public bool IsNullable {
 176                         get { return LookupIsNullable (); }
 177                 }
 178
 179                 public bool IsPublic {
 180                         get { return LookupIsPublic (); }
 181                 }
 182
 183                 public bool IsUnknown {
 184                         get { return LookupIsUnknown (); }
 185                 }
 186
 187                 public bool IsUsableDuringInitialization {
 188                         get { return LookupUsableDuringInitialization (); }
 189                 }
 190
 191                 public bool IsWhitespaceSignificantCollection {
 192                         get { return LookupIsWhitespaceSignificantCollection (); }
 193                 }
 194
 195                 public bool IsXData {
 196                         get { return LookupIsXData (); }
 197                 }
 198
 199                 public XamlType ItemType {
 200                         get { return LookupItemType (); }
 201                 }
 202
 203                 public XamlType KeyType {
 204                         get { return LookupKeyType (); }
 205                 }
 206
 207                 public XamlType MarkupExtensionReturnType {
 208                         get { return LookupMarkupExtensionReturnType (); }
 209                 }
 210
 211                 public string Name { get; private set; }
 212
 213                 public string PreferredXamlNamespace { get; private set; }
 214
 215                 public XamlSchemaContext SchemaContext { get; private set; }
 216
 217                 public bool TrimSurroundingWhitespace {
 218                         get { return LookupTrimSurroundingWhitespace (); }
 219                 }
 220
 221                 public IList<XamlType> TypeArguments { get; private set; }
 222
 223                 public XamlValueConverter<TypeConverter> TypeConverter {
 224                         get { return LookupTypeConverter (); }
 225                 }
 226
 227                 public Type UnderlyingType {
 228                         get { return LookupUnderlyingType (); }
 229                 }
 230
 231                 public XamlValueConverter<ValueSerializer> ValueSerializer {
 232                         get { return LookupValueSerializer (); }
 233                 }
 234
 235                 public static bool operator == (XamlType left, XamlType right)
 236                 {
 237                         return IsNull (left) ? IsNull (right) : left.Equals (right);
 238                 }
 239
 240                 static bool IsNull (XamlType a)
 241                 {
 242                         return Object.ReferenceEquals (a, null);
 243                 }
 244
 245                 public static bool operator != (XamlType left, XamlType right)
 246                 {
 247                         return !(left == right);
 248                 }
 249
 250                 public bool Equals (XamlType other)
 251                 {
 252                         return !IsNull (other) &&
 253                                 UnderlyingType == other.UnderlyingType &&
 254                                 Name == other.Name &&
 255                                 PreferredXamlNamespace == other.PreferredXamlNamespace && TypeArguments.ListEquals (other.TypeArguments);
 256                 }
 257
 258                 public override bool Equals (object obj)
 259                 {
 260                         var a = obj as XamlType;
 261                         return Equals (a);
 262                 }
 263
 264                 public override int GetHashCode ()
 265                 {
 266                         if (UnderlyingType != null)
 267                                 return UnderlyingType.GetHashCode ();
 268                         int x = Name.GetHashCode () << 7 + PreferredXamlNamespace.GetHashCode ();
 269                         if (TypeArguments != null)
 270                                 foreach (var t in TypeArguments)
 271                                         x = t.GetHashCode () + x << 5;
 272                         return x;
 273                 }
 274
 275                 public override string ToString ()
 276                 {
 277                         return String.IsNullOrEmpty (PreferredXamlNamespace) ? Name : String.Concat ("{", PreferredXamlNamespace, "}", Name);
 278                 }
 279
 280                 public virtual bool CanAssignTo (XamlType xamlType)
 281                 {
 282                         throw new NotImplementedException ();
 283                 }
 284
 285                 public XamlMember GetAliasedProperty (XamlDirective directive)
 286                 {
 287                         return LookupAliasedProperty (directive);
 288                 }
 289
 290                 public ICollection<XamlMember> GetAllAttachableMembers ()
 291                 {
 292                         return new List<XamlMember> (LookupAllAttachableMembers ());
 293                 }
 294
 295                 public ICollection<XamlMember> GetAllMembers ()
 296                 {
 297                         return new List<XamlMember> (LookupAllMembers ());
 298                 }
 299
 300                 public XamlMember GetAttachableMember (string name)
 301                 {
 302                         return LookupAttachableMember (name);
 303                 }
 304
 305                 public XamlMember GetMember (string name)
 306                 {
 307                         return LookupMember (name, false);
 308                 }
 309
 310                 public IList<XamlType> GetPositionalParameters (int parameterCount)
 311                 {
 312                         return LookupPositionalParameters (parameterCount);
 313                 }
 314
 315                 public virtual IList<string> GetXamlNamespaces ()
 316                 {
 317                         throw new NotImplementedException ();
 318                         /* this does not work like documented!
 319                         if (explicit_ns != null)
 320                                 return new string [] {explicit_ns};
 321                         var l = SchemaContext.GetAllXamlNamespaces ();
 322                         if (l != null)
 323                                 return new List<string> (l);
 324                         return new string [] {String.Empty};
 325                         */
 326                 }
 327
 328                 // lookups
 329
 330                 protected virtual XamlMember LookupAliasedProperty (XamlDirective directive)
 331                 {
 332                         if (directive == XamlLanguage.Key) {
 333                                 var a = this.GetCustomAttribute<DictionaryKeyPropertyAttribute> ();
 334                                 return a != null ? GetMember (a.Name) : null;
 335                         }
 336                         if (directive == XamlLanguage.Name) {
 337                                 var a = this.GetCustomAttribute<RuntimeNamePropertyAttribute> ();
 338                                 return a != null ? GetMember (a.Name) : null;
 339                         }
 340                         if (directive == XamlLanguage.Uid) {
 341                                 var a = this.GetCustomAttribute<UidPropertyAttribute> ();
 342                                 return a != null ? GetMember (a.Name) : null;
 343                         }
 344                         if (directive == XamlLanguage.Lang) {
 345                                 var a = this.GetCustomAttribute<XmlLangPropertyAttribute> ();
 346                                 return a != null ? GetMember (a.Name) : null;
 347                         }
 348                         return null;
 349                 }
 350
 351                 protected virtual IEnumerable<XamlMember> LookupAllAttachableMembers ()
 352                 {
 353                         if (UnderlyingType == null)
 354                                 return BaseType != null ? BaseType.GetAllMembers () : null;
 355                         return DoLookupAllAttachableMembers ();
 356                 }
 357
 358                 IEnumerable<XamlMember> DoLookupAllAttachableMembers ()
 359                 {
 360                         yield break; // FIXME: what to return here?
 361                 }
 362
 363                 protected virtual IEnumerable<XamlMember> LookupAllMembers ()
 364                 {
 365                         if (UnderlyingType == null)
 366                                 return BaseType != null ? BaseType.GetAllMembers () : null;
 367                         if (all_members_cache == null)
 368                                 all_members_cache = new List<XamlMember> (DoLookupAllMembers ());
 369                         return all_members_cache;
 370                 }
 371
 372                 List<XamlMember> all_members_cache;
 373
 374                 IEnumerable<XamlMember> DoLookupAllMembers ()
 375                 {
 376                         foreach (var pi in UnderlyingType.GetProperties ())
 377                                 if (pi.CanRead && pi.CanWrite && pi.GetIndexParameters ().Length == 0)
 378                                         yield return new XamlMember (pi, SchemaContext);
 379                 }
 380
 381                 protected virtual IList<XamlType> LookupAllowedContentTypes ()
 382                 {
 383                         // the actual implementation is very different from what is documented :(
 384                         return null;
 385
 386                         /*
 387                         var l = new List<XamlType> ();
 388                         if (ContentWrappers != null)
 389                                 l.AddRange (ContentWrappers);
 390                         if (ContentProperty != null)
 391                                 l.Add (ContentProperty.Type);
 392                         if (ItemType != null)
 393                                 l.Add (ItemType);
 394                         return l.Count > 0 ? l : null;
 395                         */
 396                 }
 397
 398                 protected virtual XamlMember LookupAttachableMember (string name)
 399                 {
 400                         throw new NotImplementedException ();
 401                 }
 402
 403                 [MonoTODO]
 404                 protected virtual XamlType LookupBaseType ()
 405                 {
 406                         if (base_type == null) {
 407                                 if (UnderlyingType == null)
 408                                         // FIXME: probably something advanced is needed here.
 409                                         base_type = new XamlType (typeof (object), SchemaContext, Invoker);
 410                                 else
 411                                         base_type = type.BaseType == null || type.BaseType == typeof (object) ? null : new XamlType (type.BaseType, SchemaContext, Invoker);
 412                         }
 413                         return base_type;
 414                 }
 415
 416                 // This implementation is not verified. (No place to use.)
 417                 protected virtual XamlCollectionKind LookupCollectionKind ()
 418                 {
 419                         if (UnderlyingType == null)
 420                                 return BaseType != null ? BaseType.LookupCollectionKind () : XamlCollectionKind.None;
 421                         if (type.IsArray)
 422                                 return XamlCollectionKind.Array;
 423
 424                         if (type.ImplementsAnyInterfacesOf (typeof (IDictionary), typeof (IDictionary<,>)))
 425                                 return XamlCollectionKind.Dictionary;
 426
 427                         if (type.ImplementsAnyInterfacesOf (typeof (ICollection), typeof (ICollection<>)))
 428                                 return XamlCollectionKind.Collection;
 429
 430                         return XamlCollectionKind.None;
 431                 }
 432
 433                 protected virtual bool LookupConstructionRequiresArguments ()
 434                 {
 435                         if (UnderlyingType == null)
 436                                 return false;
 437
 438                         // not sure if it is required, but MemberDefinition return true while they are abstract and it makes no sense.
 439                         if (UnderlyingType.IsAbstract)
 440                                 return true;
 441
 442                         // FIXME: probably some primitive types are treated as special.
 443                         switch (Type.GetTypeCode (UnderlyingType)) {
 444                         case TypeCode.String:
 445                                 return true;
 446                         case TypeCode.Object:
 447                                 if (UnderlyingType == typeof (TimeSpan))
 448                                         return false;
 449                                 break;
 450                         default:
 451                                 return false;
 452                         }
 453
 454                         return UnderlyingType.GetConstructor (BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, null, Type.EmptyTypes, null) == null;
 455                 }
 456
 457                 protected virtual XamlMember LookupContentProperty ()
 458                 {
 459                         var a = this.GetCustomAttribute<ContentPropertyAttribute> ();
 460                         return a != null && a.Name != null ? GetMember (a.Name) : null;
 461                 }
 462
 463                 protected virtual IList<XamlType> LookupContentWrappers ()
 464                 {
 465                         if (CustomAttributeProvider == null)
 466                                 return null;
 467
 468                         var arr = CustomAttributeProvider.GetCustomAttributes (typeof (ContentWrapperAttribute), false);
 469                         if (arr == null || arr.Length == 0)
 470                                 return null;
 471                         var l = new XamlType [arr.Length];
 472                         for (int i = 0; i < l.Length; i++)
 473                                 l [i] = SchemaContext.GetXamlType (((ContentWrapperAttribute) arr [i]).ContentWrapper);
 474                         return l;
 475                 }
 476
 477                 internal ICustomAttributeProvider CustomAttributeProvider {
 478                         get { return LookupCustomAttributeProvider (); }
 479                 }
 480
 481                 protected virtual ICustomAttributeProvider LookupCustomAttributeProvider ()
 482                 {
 483                         return UnderlyingType;
 484                 }
 485                 protected virtual XamlValueConverter<XamlDeferringLoader> LookupDeferringLoader ()
 486                 {
 487                         throw new NotImplementedException ();
 488                 }
 489
 490                 protected virtual XamlTypeInvoker LookupInvoker ()
 491                 {
 492                         return invoker;
 493                 }
 494
 495                 protected virtual bool LookupIsAmbient ()
 496                 {
 497                         return this.GetCustomAttribute<AmbientAttribute> () != null;
 498                 }
 499
 500                 // It is documented as if it were to reflect spec. section 5.2,
 501                 // but the actual behavior shows it is *totally* wrong.
 502                 // Here I have implemented this based on the nunit test results. sigh.
 503                 protected virtual bool LookupIsConstructible ()
 504                 {
 505                         if (UnderlyingType == null)
 506                                 return true;
 507                         if (IsMarkupExtension)
 508                                 return true;
 509                         if (UnderlyingType.IsAbstract)
 510                                 return false;
 511                         if (!IsNameValid)
 512                                 return false;
 513                         return true;
 514                 }
 515
 516                 protected virtual bool LookupIsMarkupExtension ()
 517                 {
 518                         return typeof (MarkupExtension).IsAssignableFrom (UnderlyingType);
 519                 }
 520
 521                 protected virtual bool LookupIsNameScope ()
 522                 {
 523                         return typeof (INameScope).IsAssignableFrom (UnderlyingType);
 524                 }
 525
 526                 protected virtual bool LookupIsNullable ()
 527                 {
 528                         return !type.IsValueType || type.ImplementsInterface (typeof (Nullable<>));
 529                 }
 530
 531                 protected virtual bool LookupIsPublic ()
 532                 {
 533                         return underlying_type == null || underlying_type.IsPublic || underlying_type.IsNestedPublic;
 534                 }
 535
 536                 protected virtual bool LookupIsUnknown ()
 537                 {
 538                         return UnderlyingType == null;
 539                 }
 540
 541                 protected virtual bool LookupIsWhitespaceSignificantCollection ()
 542                 {
 543                         // probably for unknown types, it should preserve whitespaces.
 544                         return IsUnknown || this.GetCustomAttribute<WhitespaceSignificantCollectionAttribute> () != null;
 545                 }
 546
 547                 protected virtual bool LookupIsXData ()
 548                 {
 549                         // huh? XamlLanguage.XData.IsXData returns false(!)
 550                         // return typeof (XData).IsAssignableFrom (UnderlyingType);
 551                         return false;
 552                 }
 553
 554                 protected virtual XamlType LookupItemType ()
 555                 {
 556                         if (IsArray)
 557                                 return new XamlType (type.GetElementType (), SchemaContext);
 558                         if (!IsCollection)
 559                                 return null;
 560                         if (!IsGeneric)
 561                                 return new XamlType (typeof (object), SchemaContext);
 562                         return new XamlType (type.GetGenericArguments () [0], SchemaContext);
 563                 }
 564
 565                 protected virtual XamlType LookupKeyType ()
 566                 {
 567                         if (!IsDictionary)
 568                                 return null;
 569                         if (!IsGeneric)
 570                                 return new XamlType (typeof (object), SchemaContext);
 571                         return new XamlType (type.GetGenericArguments () [0], SchemaContext);
 572                 }
 573
 574                 protected virtual XamlType LookupMarkupExtensionReturnType ()
 575                 {
 576                         var a = this.GetCustomAttribute<MarkupExtensionReturnTypeAttribute> ();
 577                         return a != null ? new XamlType (a.ReturnType, SchemaContext) : null;
 578                 }
 579
 580                 protected virtual XamlMember LookupMember (string name, bool skipReadOnlyCheck)
 581                 {
 582                         if (UnderlyingType == null)
 583                                 return null;
 584                         var pi = UnderlyingType.GetProperty (name);
 585                         if (pi != null && (skipReadOnlyCheck || pi.CanWrite))
 586                                 return new XamlMember (pi, SchemaContext);
 587                         var ei = UnderlyingType.GetEvent (name);
 588                         if (ei != null)
 589                                 return new XamlMember (ei, SchemaContext);
 590                         return null;
 591                 }
 592
 593                 protected virtual IList<XamlType> LookupPositionalParameters (int parameterCount)
 594                 {
 595                         if (UnderlyingType == null/* || !IsMarkupExtension*/) // see nunit tests...
 596                                 return null;
 597
 598                         // check if there is applicable ConstructorArgumentAttribute.
 599                         // If there is, then return its type.
 600                         if (parameterCount == 1) {
 601                                 foreach (var xm in GetAllMembers ()) {
 602                                         var ca = xm.CustomAttributeProvider.GetCustomAttribute<ConstructorArgumentAttribute> (false);
 603                                         if (ca != null)
 604                                                 return new XamlType [] {xm.Type};
 605                                 }
 606                         }
 607
 608                         var methods = (from m in UnderlyingType.GetConstructors (BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance) where m.GetParameters ().Length == parameterCount select m).ToArray ();
 609                         if (methods.Length == 1)
 610                                 return (from p in methods [0].GetParameters () select SchemaContext.GetXamlType (p.ParameterType)).ToArray ();
 611
 612                         if (SchemaContext.SupportMarkupExtensionsWithDuplicateArity)
 613                                 throw new NotSupportedException ("The default LookupPositionalParameters implementation does not allow duplicate arity of markup extensions");
 614                         return null;
 615                 }
 616
 617                 BindingFlags flags_get_static = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static;
 618
 619                 protected virtual EventHandler<XamlSetMarkupExtensionEventArgs> LookupSetMarkupExtensionHandler ()
 620                 {
 621                         var a = this.GetCustomAttribute<XamlSetMarkupExtensionAttribute> ();
 622                         if (a == null)
 623                                 return null;
 624                         var mi = type.GetMethod (a.XamlSetMarkupExtensionHandler, flags_get_static);
 625                         if (mi == null)
 626                                 throw new ArgumentException ("Binding to XamlSetMarkupExtensionHandler failed");
 627                         return (EventHandler<XamlSetMarkupExtensionEventArgs>) Delegate.CreateDelegate (typeof (EventHandler<XamlSetMarkupExtensionEventArgs>), mi);
 628                 }
 629
 630                 protected virtual EventHandler<XamlSetTypeConverterEventArgs> LookupSetTypeConverterHandler ()
 631                 {
 632                         var a = this.GetCustomAttribute<XamlSetTypeConverterAttribute> ();
 633                         if (a == null)
 634                                 return null;
 635                         var mi = type.GetMethod (a.XamlSetTypeConverterHandler, flags_get_static);
 636                         if (mi == null)
 637                                 throw new ArgumentException ("Binding to XamlSetTypeConverterHandler failed");
 638                         return (EventHandler<XamlSetTypeConverterEventArgs>) Delegate.CreateDelegate (typeof (EventHandler<XamlSetTypeConverterEventArgs>), mi);
 639                 }
 640
 641                 protected virtual bool LookupTrimSurroundingWhitespace ()
 642                 {
 643                         return this.GetCustomAttribute<TrimSurroundingWhitespaceAttribute> () != null;
 644                 }
 645
 646                 protected virtual XamlValueConverter<TypeConverter> LookupTypeConverter ()
 647                 {
 648                         var t = UnderlyingType;
 649                         if (t == null)
 650                                 return null;
 651
 652                         // equivalent to TypeExtension.
 653                         // FIXME: not sure if it should be specially handled here.
 654                         if (t == typeof (Type))
 655                                 t = typeof (TypeExtension);
 656
 657                         var a = CustomAttributeProvider.GetCustomAttribute<TypeConverterAttribute> (false);
 658                         if (a != null)
 659                                 return SchemaContext.GetValueConverter<TypeConverter> (Type.GetType (a.ConverterTypeName), this);
 660
 661                         if (t == typeof (object))
 662                                 return SchemaContext.GetValueConverter<TypeConverter> (typeof (TypeConverter), this);
 663
 664                         // It's still not decent to check CollectionConverter.
 665                         var tct = TypeDescriptor.GetConverter (t).GetType ();
 666                         if (tct != typeof (TypeConverter) && tct != typeof (CollectionConverter) && tct != typeof (ReferenceConverter))
 667                                 return SchemaContext.GetValueConverter<TypeConverter> (tct, this);
 668                         return null;
 669                 }
 670
 671                 protected virtual Type LookupUnderlyingType ()
 672                 {
 673                         return underlying_type;
 674                 }
 675
 676                 protected virtual bool LookupUsableDuringInitialization ()
 677                 {
 678                         var a = this.GetCustomAttribute<UsableDuringInitializationAttribute> ();
 679                         return a != null && a.Usable;
 680                 }
 681
 682                 static XamlValueConverter<ValueSerializer> string_value_serializer;
 683
 684                 protected virtual XamlValueConverter<ValueSerializer> LookupValueSerializer ()
 685                 {
 686                         return LookupValueSerializer (this, CustomAttributeProvider);
 687                 }
 688
 689                 internal static XamlValueConverter<ValueSerializer> LookupValueSerializer (XamlType targetType, ICustomAttributeProvider provider)
 690                 {
 691                         if (provider == null)
 692                                 return null;
 693
 694                         var a = provider.GetCustomAttribute<ValueSerializerAttribute> (true);
 695                         if (a != null)
 696                                 return new XamlValueConverter<ValueSerializer> (a.ValueSerializerType ?? Type.GetType (a.ValueSerializerTypeName), targetType);
 697
 698                         if (targetType.BaseType != null) {
 699                                 var ret = targetType.BaseType.LookupValueSerializer ();
 700                                 if (ret != null)
 701                                         return ret;
 702                         }
 703
 704                         if (targetType.UnderlyingType == typeof (string)) {
 705                                 if (string_value_serializer == null)
 706                                         string_value_serializer = new XamlValueConverter<ValueSerializer> (typeof (StringValueSerializer), targetType);
 707                                 return string_value_serializer;
 708                         }
 709
 710                         return null;
 711                 }
 712
 713                 internal IEnumerable<XamlMember> GetConstructorArguments ()
 714                 {
 715                         return GetAllMembers ().Where (m => m.UnderlyingMember != null && m.CustomAttributeProvider.GetCustomAttribute<ConstructorArgumentAttribute> (false) != null);
 716                 }
 717         }
 718 }