| IndexKeysDefinitionExtensionsGeoHaystackTDocument Method (IndexKeysDefinitionTDocument, ExpressionFuncTDocument, Object, ExpressionFuncTDocument, Object) | 
 Note: This API is now obsolete.
            Combines an existing index keys definition with a geo haystack index key definition.
            
 
    Namespace: 
   MongoDB.Driver
    Assembly:
   MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.12.2+a4a3888f4fb51bb518b1eb5002effc2d47f2ea6a
 Syntax
Syntax[ObsoleteAttribute("GeoHaystack indexes were deprecated in server version 4.4.")]
public static IndexKeysDefinition<TDocument> GeoHaystack<TDocument>(
	this IndexKeysDefinition<TDocument> keys,
	Expression<Func<TDocument, Object>> field,
	Expression<Func<TDocument, Object>> additionalFieldName = null
)
<ExtensionAttribute>
<ObsoleteAttribute("GeoHaystack indexes were deprecated in server version 4.4.")>
Public Shared Function GeoHaystack(Of TDocument) ( 
	keys As IndexKeysDefinition(Of TDocument),
	field As Expression(Of Func(Of TDocument, Object)),
	Optional additionalFieldName As Expression(Of Func(Of TDocument, Object)) = Nothing
) As IndexKeysDefinition(Of TDocument)[<ExtensionAttribute>]
[<ObsoleteAttribute("GeoHaystack indexes were deprecated in server version 4.4.")>]
static member GeoHaystack : 
        keys : IndexKeysDefinition<'TDocument> * 
        field : Expression<Func<'TDocument, Object>> * 
        ?additionalFieldName : Expression<Func<'TDocument, Object>> 
(* Defaults:
        let _additionalFieldName = defaultArg additionalFieldName null
*)
-> IndexKeysDefinition<'TDocument> 
Parameters
- keys
- Type: MongoDB.DriverIndexKeysDefinitionTDocument
 The keys.
- field
- Type: System.Linq.ExpressionsExpressionFuncTDocument, Object
 The field.
- additionalFieldName (Optional)
- Type: System.Linq.ExpressionsExpressionFuncTDocument, Object
 Name of the additional field.
Type Parameters
- TDocument
- The type of the document.
Return Value
Type: 
IndexKeysDefinitionTDocument
            A combined index keys definition.
            
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type 
IndexKeysDefinitionTDocument. 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