| IAggregateFluentTResultLookupTForeignDocument, TAsElement, TAs, TNewResult Method (IMongoCollectionTForeignDocument, BsonDocument, PipelineDefinitionTForeignDocument, TAsElement, FieldDefinitionTNewResult, TAs, AggregateLookupOptionsTForeignDocument, TNewResult) | 
 
            Appends a lookup stage to the pipeline.
            
 
    Namespace: 
   MongoDB.Driver
    Assembly:
   MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.12.2+a4a3888f4fb51bb518b1eb5002effc2d47f2ea6a
 Syntax
SyntaxIAggregateFluent<TNewResult> Lookup<TForeignDocument, TAsElement, TAs, TNewResult>(
	IMongoCollection<TForeignDocument> foreignCollection,
	BsonDocument let,
	PipelineDefinition<TForeignDocument, TAsElement> lookupPipeline,
	FieldDefinition<TNewResult, TAs> as,
	AggregateLookupOptions<TForeignDocument, TNewResult> options = null
)
where TAs : Object, IEnumerable<TAsElement>
Function Lookup(Of TForeignDocument, TAsElement, TAs As {Object, IEnumerable(Of TAsElement)}, TNewResult) ( 
	foreignCollection As IMongoCollection(Of TForeignDocument),
	let As BsonDocument,
	lookupPipeline As PipelineDefinition(Of TForeignDocument, TAsElement),
	as As FieldDefinition(Of TNewResult, TAs),
	Optional options As AggregateLookupOptions(Of TForeignDocument, TNewResult) = Nothing
) As IAggregateFluent(Of TNewResult)abstract Lookup : 
        foreignCollection : IMongoCollection<'TForeignDocument> * 
        let : BsonDocument * 
        lookupPipeline : PipelineDefinition<'TForeignDocument, 'TAsElement> * 
        as : FieldDefinition<'TNewResult, 'TAs> * 
        ?options : AggregateLookupOptions<'TForeignDocument, 'TNewResult> 
(* Defaults:
        let _options = defaultArg options null
*)
-> IAggregateFluent<'TNewResult>  when 'TAs : Object and IEnumerable<'TAsElement>
Parameters
- foreignCollection
- Type: MongoDB.DriverIMongoCollectionTForeignDocument
 The foreign collection.
- let
- Type: MongoDB.BsonBsonDocument
 The "let" definition.
- lookupPipeline
- Type: MongoDB.DriverPipelineDefinitionTForeignDocument, TAsElement
 The lookup pipeline.
- as
- Type: MongoDB.DriverFieldDefinitionTNewResult, TAs
 The as field in TNewResult in which to place the results of the lookup pipeline.
- options (Optional)
- Type: MongoDB.DriverAggregateLookupOptionsTForeignDocument, TNewResult
 The options.
Type Parameters
- TForeignDocument
- The type of the foreign collection documents.
- TAsElement
- The type of the as field elements.
- TAs
- The type of the as field.
- TNewResult
- The type of the new result.
Return Value
Type: 
IAggregateFluentTNewResultThe fluent aggregate interface.
 See Also
See Also