fixed projection problems with inheritance

source/MongoDB/Cursor_1.cs

@@ -5,6 +5,9 @@
 using MongoDB.Protocol;
 using MongoDB.Serialization;
 using System.Linq;
+using MongoDB.Util;
+using MongoDB.Configuration.Mapping.Model;
+using MongoDB.Configuration.Mapping;
 
 namespace MongoDB
 {
@@ -25,6 +28,7 @@ public class Cursor<T> : ICursor<T> where T : class
         private int _skip;
         private bool _keepCursor;
         private readonly ISerializationFactory _serializationFactory;
+        private readonly IMappingStore _mappingStore;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Cursor&lt;T&gt;"/> class.
@@ -33,14 +37,15 @@ public class Cursor<T> : ICursor<T> where T : class
         /// <param name="connection">The conn.</param>
         /// <param name="databaseName">Name of the database.</param>
         /// <param name="collectionName">Name of the collection.</param>
-        internal Cursor(ISerializationFactory serializationFactory, Connection connection, string databaseName, string collectionName)
+        internal Cursor(ISerializationFactory serializationFactory, IMappingStore mappingStore, Connection connection, string databaseName, string collectionName)
         {
             //Todo: add public constrcutor for users to call
             IsModifiable = true;
             _connection = connection;
             _databaseName = databaseName;
             FullCollectionName = databaseName + "." + collectionName;
             _serializationFactory = serializationFactory;
+            _mappingStore = mappingStore;
         }
 
         /// <summary>
@@ -54,8 +59,8 @@ internal Cursor(ISerializationFactory serializationFactory, Connection connectio
         /// <param name="limit">The limit.</param>
         /// <param name="skip">The skip.</param>
         /// <param name="fields">The fields.</param>
-        internal Cursor(ISerializationFactory serializationFactory, Connection connection, string databaseName, string collectionName, object spec, int limit, int skip, object fields)
-            : this(serializationFactory, connection, databaseName, collectionName)
+        internal Cursor(ISerializationFactory serializationFactory, IMappingStore mappingStore, Connection connection, string databaseName, string collectionName, object spec, int limit, int skip, object fields)
+            : this(serializationFactory, mappingStore, connection, databaseName, collectionName)
         {
             //Todo: add public constrcutor for users to call
             if (spec == null)
@@ -333,7 +338,7 @@ private void KillCursor(long cursorId)
                     NumberToReturn = _limit,
                     NumberToSkip = _skip,
                     Options = _options,
-                    ReturnFieldSelector = _fields
+                    ReturnFieldSelector = ConvertFieldSelectorToDocument(_fields)
                 };
             }
             else
@@ -391,5 +396,52 @@ private void KillCursor(long cursorId)
             document["$query"] = _spec;
             return document;
         }
+
+        private Document ConvertFieldSelectorToDocument(object document)
+        {
+            Document doc;
+            if (document == null)
+                doc = new Document();
+            else
+                doc = ConvertExampleToDocument(document) as Document;
+
+            if (doc == null)
+                throw new NotSupportedException("An entity type is not supported in field selection. Use either a document or an anonymous type.");
+
+            var classMap = _mappingStore.GetClassMap(typeof(T));
+            if (doc.Count > 0 && (classMap.IsPolymorphic || classMap.IsSubClass))
+                doc[classMap.DiscriminatorAlias] = true;
+
+            return doc.Count == 0 ? null : doc;
+        }
+
+        private object ConvertExampleToDocument(object document)
+        {
+            if (document == null)
+                return null;
+
+            Document doc = document as Document;
+            if (doc != null)
+                return doc;
+
+            doc = new Document();
+
+            if (!(document is T)) //some type that is being used as an example
+            {
+                foreach (var prop in document.GetType().GetProperties())
+                {
+                    if (!prop.CanRead)
+                        continue;
+
+                    object value = prop.GetValue(document, null);
+                    if (!TypeHelper.IsNativeToMongo(prop.PropertyType))
+                        value = ConvertExampleToDocument(value);
+
+                    doc[prop.Name] = value;
+                }
+            }
+
+            return doc;
+        }
     }
-}
+}

source/MongoDB/MongoCollection_1.cs

@@ -159,7 +159,7 @@ public T FindOne(string javascriptWhere)
         public ICursor<T> Find(object spec, int limit, int skip, object fields){
             if (spec == null)
                 spec = new Document();
-            return new Cursor<T>(_configuration.SerializationFactory, _connection, DatabaseName, Name, spec, limit, skip, fields);
+            return new Cursor<T>(_configuration.SerializationFactory, _configuration.MappingStore, _connection, DatabaseName, Name, spec, limit, skip, fields);
         }
 
         /// <summary>
@@ -603,25 +603,5 @@ private object EnsureUpdateDocument(object document)
 
             return document;
         }
-
-        private Document ConvertObjectToDocument(object document)
-        {
-            Document doc = document as Document;
-            if (doc != null)
-                return doc;
-
-            if (document is T)
-            {
-                var classMap = _configuration.MappingStore.GetClassMap(typeof(T));
-                foreach (PersistentMemberMap memberMap in classMap)
-                {
-                    doc[memberMap.MemberName] = memberMap.GetValue(document);
-                }
-            }
-            else //anonymous type...
-            {
-
-            }
-        }
     }
 }

source/MongoDB/Protocol/QueryMessage.cs

@@ -17,7 +17,7 @@ namespace MongoDB.Protocol
     ///     [ BSON      returnFieldSelector; ]  // OPTIONAL : selector indicating the fields to return.  See below for details.
     /// }
     /// </remarks>
-    internal class QueryMessage<T> : RequestMessageBase
+    internal class QueryMessage : RequestMessageBase
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="QueryMessage"/> class.

source/MongoDB/Util/TypeHelper.cs

@@ -54,5 +54,24 @@ internal static Type GetNonNullableType(Type type)
         {
             return IsNullableType(type) ? type.GetGenericArguments()[0] : type;
         }
+
+        internal static bool IsNativeToMongo(Type type)
+        {
+            var typeCode = Type.GetTypeCode(type);
+
+            if (typeCode != TypeCode.Object)
+                return true;
+
+            if (type == typeof(Guid))
+                return true;
+
+            if (type == typeof(Oid))
+                return true;
+
+            if (type == typeof(byte[]))
+                return true;
+
+            return false;
+        }
     }
 }