| IAggregateFluentExtensionsLookupTResult Method (IAggregateFluentTResult, String, FieldDefinitionTResult, FieldDefinitionBsonDocument, FieldDefinitionBsonDocument) | 
 
            Appends a lookup stage to the pipeline.
            
 
    Namespace: 
   MongoDB.Driver
    Assembly:
   MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.12.2+a4a3888f4fb51bb518b1eb5002effc2d47f2ea6a
 Syntax
Syntaxpublic static IAggregateFluent<BsonDocument> Lookup<TResult>(
	this IAggregateFluent<TResult> aggregate,
	string foreignCollectionName,
	FieldDefinition<TResult> localField,
	FieldDefinition<BsonDocument> foreignField,
	FieldDefinition<BsonDocument> as
)
<ExtensionAttribute>
Public Shared Function Lookup(Of TResult) ( 
	aggregate As IAggregateFluent(Of TResult),
	foreignCollectionName As String,
	localField As FieldDefinition(Of TResult),
	foreignField As FieldDefinition(Of BsonDocument),
	as As FieldDefinition(Of BsonDocument)
) As IAggregateFluent(Of BsonDocument)
[<ExtensionAttribute>]
static member Lookup : 
        aggregate : IAggregateFluent<'TResult> * 
        foreignCollectionName : string * 
        localField : FieldDefinition<'TResult> * 
        foreignField : FieldDefinition<BsonDocument> * 
        as : FieldDefinition<BsonDocument> -> IAggregateFluent<BsonDocument> 
Parameters
- aggregate
- Type: MongoDB.DriverIAggregateFluentTResult
 The aggregate.
- foreignCollectionName
- Type: SystemString
 Name of the foreign collection.
- localField
- Type: MongoDB.DriverFieldDefinitionTResult
 The local field.
- foreignField
- Type: MongoDB.DriverFieldDefinitionBsonDocument
 The foreign field.
- as
- Type: MongoDB.DriverFieldDefinitionBsonDocument
 The field in the result to place the foreign matches.
Type Parameters
- TResult
- The type of the result.
Return Value
Type: 
IAggregateFluentBsonDocumentThe fluent aggregate interface.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type 
IAggregateFluentTResult. When you use instance method syntax to call this method, omit the first parameter. For more information, see 
Extension Methods (Visual Basic) or 
Extension Methods (C# Programming Guide).
 See Also
See Also