mcs/class/System.Web/System.Web.Util/DataSourceResolver.cs

   1 //
   2 // System.Web.Util.DataSourceResolver
   3 //
   4 // Authors:
   5 //      Ben Maurer (bmaurer@novell.com)
   6 //
   7 // (C) 2005 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 //
  30 // This is from
  31 // _Developing Microsoft ASP.NET Server Controls and Components_ (Kothari, Datye)
  32 //    Listing 20-3 "GetDataSource" (page 564)
  33 //
  34
  35 using System.Collections;
  36 using System.ComponentModel;
  37
  38 namespace System.Web.Util {
  39         class DataSourceResolver
  40         {
  41                 DataSourceResolver () {}
  42
  43                 public static IEnumerable ResolveDataSource (object o, string data_member)
  44                 {
  45                         IEnumerable ds;
  46
  47                         ds = o as IEnumerable;
  48                         if (ds != null)
  49                                 return ds;
  50
  51                         IListSource ls = o as IListSource;
  52
  53                         if (ls == null)
  54                                 return null;
  55
  56                         IList member_list = ls.GetList ();
  57                         if (! ls.ContainsListCollection)
  58                                 return member_list;
  59
  60                         ITypedList tl = member_list as ITypedList;
  61                         if (tl == null)
  62                                 return null;
  63
  64                         PropertyDescriptorCollection pd = tl.GetItemProperties (new PropertyDescriptor [0]);
  65
  66                         if (pd == null || pd.Count == 0)
  67                                 throw new HttpException ("The selected data source did not contain any data members to bind to");
  68
  69                         PropertyDescriptor member_desc = data_member == "" ?
  70                                 pd [0] :
  71                                 pd.Find (data_member, true);
  72
  73                         if (member_desc != null)
  74                                 ds = member_desc.GetValue (member_list [0]) as IEnumerable;
  75
  76                         if (ds == null)
  77                                 throw new HttpException ("A list corresponding to the selected DataMember was not found");
  78
  79                         return ds;
  80                 }
  81         }
  82 }