CSHARP-1521: added support for querying dictionaries serialized as array of documents.

Author: craiggwilson

src/MongoDB.Bson/Serialization/Serializers/DictionarySerializerBase.cs

@@ -338,6 +338,7 @@ private string SerializeKeyString(object key)
  /// <typeparam name="TValue">The type of the values.</typeparam>
  public abstract class DictionarySerializerBase<TDictionary, TKey, TValue> :
  ClassSerializerBase<TDictionary>,
+ IBsonArraySerializer,
  IBsonDocumentSerializer,
  IBsonDictionarySerializer
  where TDictionary : class, IDictionary<TKey, TValue>
@@ -463,6 +464,26 @@ public IBsonSerializer<TValue> ValueSerializer
  }
 
  // public methods
+ /// <inheritdoc/>
+ public bool TryGetItemSerializationInfo(out BsonSerializationInfo serializationInfo)
+ {
+ if (_dictionaryRepresentation != DictionaryRepresentation.ArrayOfDocuments)
+ {
+ serializationInfo = null;
+ return false;
+ }
+
+ var serializer = new KeyValuePairSerializer<TKey, TValue>(
+ BsonType.Document,
+ _lazyKeySerializer.Value,
+ _lazyValueSerializer.Value);
+ serializationInfo = new BsonSerializationInfo(
+ null,
+ serializer,
+ serializer.ValueType);
+ return true;
+ }
+
  /// <inheritdoc/>
  public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
  {

src/MongoDB.Bson/Serialization/Serializers/KeyValuePairSerializer.cs

@@ -27,7 +27,9 @@ namespace MongoDB.Bson.Serialization.Serializers
  /// </summary>
  /// <typeparam name="TKey">The type of the keys.</typeparam>
  /// <typeparam name="TValue">The type of the values.</typeparam>
- public class KeyValuePairSerializer<TKey, TValue> : StructSerializerBase<KeyValuePair<TKey, TValue>>
+ public class KeyValuePairSerializer<TKey, TValue> :
+ StructSerializerBase<KeyValuePair<TKey, TValue>>,
+ IBsonDocumentSerializer
  {
  // private constants
  private static class Flags
@@ -206,6 +208,29 @@ public override void Serialize(BsonSerializationContext context, BsonSerializati
  }
  }
 
+ /// <inheritdoc />
+ public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
+ {
+ if (_representation != BsonType.Document)
+ {
+ serializationInfo = null;
+ return false;
+ }
+
+ switch (memberName)
+ {
+ case "Key":
+ serializationInfo = new BsonSerializationInfo("k", _lazyKeySerializer.Value, _lazyKeySerializer.Value.ValueType);
+ return true;
+ case "Value":
+ serializationInfo = new BsonSerializationInfo("v", _lazyValueSerializer.Value, _lazyValueSerializer.Value.ValueType);
+ return true;
+ }
+
+ serializationInfo = null;
+ return false;
+ }
+
  // private methods
  private KeyValuePair<TKey, TValue> DeserializeArrayRepresentation(BsonDeserializationContext context)
  {

src/MongoDB.Driver.Tests/FilterDefinitionBuilderTests.cs

@@ -14,6 +14,7 @@
 */
 
 using System;
+using System.Collections.Generic;
 using System.Linq.Expressions;
 using FluentAssertions;
 using MongoDB.Bson;
@@ -209,6 +210,15 @@ public void ElemMatch_Typed()
  Assert(subject.ElemMatch(x => x.Pets, x => x.Name == "Fluffy"), "{pets: {$elemMatch: {name: 'Fluffy'}}}");
  }
 
+ [Test]
+ public void ElemMatch_over_dictionary_represented_as_array_of_documents()
+ {
+ var subject = CreateSubject<Feature>();
+ var filter = subject.ElemMatch(x => x.Enabled, x => x.Key == ProductType.Auto && x.Value);
+
+ Assert(filter, "{Enabled: {$elemMatch: { k: 0, v: true}}}");
+ }
+
  [Test]
  public void Empty()
  {
@@ -992,5 +1002,19 @@ private class Dog : Mammal
  [BsonElement("isLapDog")]
  public bool IsLapDog { get; set; }
  }
+
+ private class Feature
+ {
+ public ObjectId Id { get; set; }
+
+ [BsonDictionaryOptions(Representation = Bson.Serialization.Options.DictionaryRepresentation.ArrayOfDocuments)]
+ public Dictionary<ProductType, bool> Enabled { get; set; }
+ }
+
+ private enum ProductType
+ {
+ Auto,
+ Home
+ }
  }
 }