mcs/class/System.Windows.Forms/System.Windows.Forms/ListBindingHelper.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
   2 // a copy of this software and associated documentation files (the
   3 // "Software"), to deal in the Software without restriction, including
   4 // without limitation the rights to use, copy, modify, merge, publish,
   5 // distribute, sublicense, and/or sell copies of the Software, and to
   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2007 Novell, Inc.
  21 //
  22 // Author:
  23 //      Carlos Alberto Cortez <calberto.cortez@gmail.com>
  24 //      Ivan Zlatev <contact@i-nz.net>
  25 //
  26
  27 using System;
  28 using System.Collections;
  29 using System.ComponentModel;
  30 using System.Reflection;
  31 using System.Collections.Generic;
  32
  33 namespace System.Windows.Forms
  34 {
  35
  36         public static class ListBindingHelper
  37         {
  38                 public static object GetList (object list)
  39                 {
  40                         if (list is IListSource)
  41                                 return ((IListSource) list).GetList ();
  42                         return list;
  43                 }
  44
  45                 public static object GetList (object dataSource, string dataMember)
  46                 {
  47                         dataSource = GetList (dataSource);
  48                         if (dataSource == null || dataMember == null || dataMember.Length == 0)
  49                                 return dataSource;
  50
  51                         PropertyDescriptor property = GetListItemProperties (dataSource).Find (dataMember, true);
  52                         if (property == null)
  53                                 throw new ArgumentException ("dataMember");
  54
  55                         object item = null;
  56
  57                         ICurrencyManagerProvider currencyManagerProvider = dataSource as ICurrencyManagerProvider;
  58                         if (currencyManagerProvider != null && currencyManagerProvider.CurrencyManager != null) {
  59                                 CurrencyManager currencyManager = currencyManagerProvider.CurrencyManager;
  60                                 if (currencyManager != null && currencyManager.Count > 0 && currencyManager.Current != null)
  61                                         item = currencyManager.Current;
  62                         }
  63
  64                         if (item == null) {
  65                                 if (dataSource is IEnumerable) {
  66                                         if (dataSource is IList) {
  67                                                 IList list = (IList) dataSource;
  68                                                 item = list.Count > 0 ? list[0] : null;
  69                                         } else {
  70                                                 IEnumerator e = ((IEnumerable) dataSource).GetEnumerator ();
  71                                                 if (e != null && e.MoveNext ())
  72                                                         item = e.Current;
  73                                         }
  74                                 } else {
  75                                         item = dataSource;
  76                                 }
  77                         }
  78
  79                         if (item != null)
  80                                 return property.GetValue (item);
  81                         return null;
  82                 }
  83
  84                 public static Type GetListItemType (object list)
  85                 {
  86                         return GetListItemType (list, String.Empty);
  87                 }
  88
  89                 public static Type GetListItemType (object dataSource, string dataMember)
  90                 {
  91                         if (dataSource == null)
  92                                 return null;
  93
  94                         if (dataMember != null && dataMember.Length > 0) {
  95                                 PropertyDescriptor property = GetProperty (dataSource, dataMember);
  96                                 if (property == null)
  97                                         return typeof (object);
  98
  99                                 return property.PropertyType;
 100                         }
 101
 102                         if (dataSource is Array)
 103                                 return dataSource.GetType ().GetElementType ();
 104
 105                         // IEnumerable seems to have higher precedence over IList
 106                         if (dataSource is IEnumerable) {
 107                                 IEnumerator enumerator = ((IEnumerable) dataSource).GetEnumerator ();
 108                                 if (enumerator.MoveNext () && enumerator.Current != null)
 109                                         return enumerator.Current.GetType ();
 110
 111                                 if (dataSource is IList || dataSource.GetType () == typeof (IList<>)) {
 112                                         PropertyInfo property = GetPropertyByReflection (dataSource.GetType (), "Item");
 113                                         if (property != null) // `Item' could be interface-explicit, and thus private
 114                                                 return property.PropertyType;
 115                                 }
 116
 117                                 // fallback to object
 118                                 return typeof (object);
 119                         }
 120
 121                         return dataSource.GetType ();
 122                 }
 123
 124                 public static PropertyDescriptorCollection GetListItemProperties (object list)
 125                 {
 126                         return GetListItemProperties (list, null);
 127                 }
 128
 129                 public static PropertyDescriptorCollection GetListItemProperties (object list, PropertyDescriptor [] listAccessors)
 130                 {
 131                         list = GetList (list);
 132
 133                         if (list == null)
 134                                 return new PropertyDescriptorCollection (null);
 135
 136                         if (list is ITypedList)
 137                                 return ((ITypedList)list).GetItemProperties (listAccessors);
 138
 139                         if (listAccessors == null || listAccessors.Length == 0) {
 140                                 Type item_type = GetListItemType (list);
 141                                 return TypeDescriptor.GetProperties (item_type,
 142                                         new Attribute [] { new BrowsableAttribute (true) });
 143                         }
 144
 145                         // Take into account only the first property
 146                         Type property_type = listAccessors [0].PropertyType;
 147                         if (typeof (IList).IsAssignableFrom (property_type) || typeof (IList<>).IsAssignableFrom (property_type)) {
 148
 149                                 PropertyInfo property = GetPropertyByReflection (property_type, "Item");
 150                                 return TypeDescriptor.GetProperties (property.PropertyType);
 151                         }
 152
 153                         return new PropertyDescriptorCollection (new PropertyDescriptor [0]);
 154                 }
 155
 156                 public static PropertyDescriptorCollection GetListItemProperties (object dataSource, string dataMember,
 157                         PropertyDescriptor [] listAccessors)
 158                 {
 159                         throw new NotImplementedException ();
 160                 }
 161
 162                 public static string GetListName (object list, PropertyDescriptor [] listAccessors)
 163                 {
 164                         if (list == null)
 165                                 return String.Empty;
 166
 167                         Type item_type = GetListItemType (list);
 168                         return item_type.Name;
 169                 }
 170
 171                 static PropertyDescriptor GetProperty (object obj, string property_name)
 172                 {
 173                         return TypeDescriptor.GetProperties (obj,
 174                                                              new Attribute [] { new BrowsableAttribute (true) })[property_name];
 175                 }
 176
 177                 //
 178                 // Need to use reflection as we need to bypass the TypeDescriptor.GetProperties () limitations
 179                 //
 180                 static PropertyInfo GetPropertyByReflection (Type type, string property_name)
 181                 {
 182                         foreach (PropertyInfo prop in type.GetProperties (BindingFlags.Public | BindingFlags.Instance))
 183                                 if (prop.Name == property_name)
 184                                         return prop;
 185
 186                         return null;
 187                 }
 188         }
 189 }