public static RenderedProjectionDefinition <TResult> TranslateGroup <TKey, TDocument, TResult>(Expression <Func <TDocument, TKey> > idProjector, Expression <Func <IGrouping <TKey, TDocument>, TResult> > groupProjector, IBsonSerializer <TDocument> parameterSerializer, IBsonSerializerRegistry serializerRegistry)
{
var keyBinder = new SerializationInfoBinder(serializerRegistry);
var boundKeyExpression = BindSerializationInfo(keyBinder, idProjector, parameterSerializer);
if (!(boundKeyExpression is ISerializationExpression))
{
var keySerializer = SerializerBuilder.Build(boundKeyExpression, serializerRegistry);
boundKeyExpression = new SerializationExpression(
boundKeyExpression,
new BsonSerializationInfo(null, keySerializer, typeof(TKey)));
}
var idExpression = new IdExpression(boundKeyExpression, ((ISerializationExpression)boundKeyExpression).SerializationInfo);
var groupBinder = new GroupSerializationInfoBinder(BsonSerializer.SerializerRegistry);
groupBinder.RegisterMemberReplacement(typeof(IGrouping <TKey, TDocument>).GetProperty("Key"), idExpression);
var groupSerializer = new ArraySerializer <TDocument>(parameterSerializer);
var boundGroupExpression = BindSerializationInfo(groupBinder, groupProjector, groupSerializer);
var projectionSerializer = (IBsonSerializer <TResult>)SerializerBuilder.Build(boundGroupExpression, serializerRegistry);
var projection = ProjectionBuilder.Build(boundGroupExpression).AsBsonDocument;
// must have an "_id" in a group document
if (!projection.Contains("_id"))
{
var idProjection = ProjectionBuilder.Build(boundKeyExpression);
projection.InsertAt(0, new BsonElement("_id", idProjection));
}
return(new RenderedProjectionDefinition <TResult>(projection, projectionSerializer));
}
public static ProjectionInfo <TResult> TranslateGroup <TKey, TDocument, TResult>(Expression <Func <TDocument, TKey> > idProjector, Expression <Func <IGrouping <TKey, TDocument>, TResult> > groupProjector, IBsonSerializer <TDocument> parameterSerializer, IBsonSerializerRegistry serializerRegistry)
{
if (groupProjector.Body.NodeType != ExpressionType.New)
{
throw new NotSupportedException("Must use an anonymous type for constructing $group pipeline operators.");
}
var keyBinder = new SerializationInfoBinder(serializerRegistry);
var boundKeyExpression = BindSerializationInfo(keyBinder, idProjector, parameterSerializer);
var groupBinder = new GroupSerializationInfoBinder(BsonSerializer.SerializerRegistry);
groupBinder.RegisterMemberReplacement(typeof(IGrouping <TKey, TDocument>).GetProperty("Key"), boundKeyExpression);
var groupSerializer = new ArraySerializer <TDocument>(parameterSerializer);
var boundGroupExpression = BindSerializationInfo(groupBinder, groupProjector, groupSerializer);
var projectionSerializer = (IBsonSerializer <TResult>)SerializerBuilder.Build(boundGroupExpression, serializerRegistry);
var projection = ProjectionBuilder.Build(boundGroupExpression).AsBsonDocument;
// must have an "_id" in a group document
if (!projection.Contains("_id"))
{
var idProjection = ProjectionBuilder.Build(boundKeyExpression);
projection.InsertAt(0, new BsonElement("_id", idProjection));
}
return(new ProjectionInfo <TResult>(projection, projectionSerializer));
}