Lightstreamer .Net Adapter 1.11.0
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IMetadataProvider.GetSchema Method

Called by Lightstreamer Kernel through the Remote Server to resolve a Field Schema name (or Field List specification) supplied in a Request. The names of the Fields in the Schema must be returned. 

Possibly, the content of a Field Schema may be dependant on the User who is issuing the Request, on the specific Session instance or on the Item Group (or Item List) to which the Request is related. 

When a A Field List specification is supplied, it is made of a space-separated list of the names of the Fields in the Schema. This convention is used by some of the subscription methods provided by the various client libraries. The specifications for these methods require that "A LiteralBasedProvider or equivalent Metadata Adapter is needed on the Server in order to understand the Request". When any of these interface methods is used by client code accessing this Metadata Adapter, the supplied "schema" argument should be inspected as a space-separated list of Field names and an array with these names in the same order should be returned; returning decorated or alternative Field names is also possible: they will be associated to the corresponding names used in the supplied Field List specification by client library code. 

This method runs in the Server thread pool specific for the Data Adapter that supplies the involved Items, if defined. 

 

C++
string[] GetSchema(string user, string sessionID, string id, string schema);
C#
string[] GetSchema(string user, string sessionID, string id, string schema);
Visual Basic
Function GetSchema(user As string, sessionID As string, id As string, schema As string) As string()
Parameters 
Description 
string user 
A User name. 
string sessionID 
The ID of a Session owned by the User. 
string id 
The name of the Item Group (or specification of the Item List) whose Items the Schema is to be applied to. 
string schema 
A Field Schema name (or Field List specification). 

An array with the names of the Fields in the Schema.

Exceptions 
Description 
in case the supplied Item Group name (or Item List specification) is not recognized.  
in case the supplied Field Schema name (or Field List specification) is not recognized.