public Expression Bind(ProjectionExpression projection, ProjectionBindingContext context, MethodCallExpression node, IEnumerable<Expression> arguments)
{
var distinct = new DistinctExpression(projection.Source, projection.Projector);
var serializer = SerializerBuilder.Build(projection.Projector, context.SerializerRegistry);
var info = new BsonSerializationInfo("_id", serializer, serializer.ValueType);
var projector = new SerializationExpression(projection.Projector, info);
return new ProjectionExpression(
distinct,
projector);
}
protected internal virtual Expression VisitDistinct(DistinctExpression node)
{
return(node.Update(Visit(node.Source)));
}
protected internal virtual Expression VisitDistinct(DistinctExpression node)
{
return node.Update(Visit(node.Source));
}
private void VisitDistinct(DistinctExpression node)
{
Visit(node.Source);
var id = new BsonDocument("_id", AggregateLanguageTranslator.Translate(node.Selector));
_stages.Add(new BsonDocument("$group", id));
}