Proficy Historian Client Access API
Proficy.Historian.ClientAccess.API Namespace / IMessages Interface / Query Method
Query details.
Query results.
Example


In This Topic
    Query Method (IMessages)
    In This Topic
    Retrieve a list of audit messages from a Historian server matching the supplied message criteria.

    For large servers clients can optionally rely on large network-message sizes or result-paging or a combination of both to retrieve a large number of messages. Maximum network-message size is straight-forward and controlled by ConnectionProperties.MaxReceivedMessageSize - it must be matched on both client and server.

    Result-paging enables large result sets to be retrieved across multiple server requests with timing and size controlled by the client. The number of results retrieved per request is controlled via the query's PageSize property. To utilize result-paging, specify a non-zero PageSize and continue calling the same query while the return code is true to retrieve all results from a server. To protect the server and limit excessive server-memory utilization initiating a second query without first retrieving all results for a first query generates a fault.

    Syntax
    Function Query( _
   ByRef query As MessageQueryParams, _
   ByRef messages As System.Collections.Generic.List(Of Message) _
) As System.Boolean
    System.bool Query( 
   ref MessageQueryParams query,
   out System.Collections.Generic.List<Message> messages
)
    System.bool Query( 
   MessageQueryParams^% query,
   [Out] System.Collections.Generic.List<Message^>^ messages
)

    Parameters

    query
    Query details.
    messages
    Query results.

    Return Value

    Whether additional results remain available on server.
    Example
    MessageQueryParams query = new MessageQueryParams();
List<Message> list = new List<Message>(), temp = null;
              
query.Criteria.Properties = MessageCriteria.PropertyFields.All;
query.Criteria.Start = DateTime.Now.AddDays(-10);
query.Criteria.Topic = Message.MessageTopic.All;
              
// simple query
connection.IMessages.Query(ref query, out list);
              
// paged query
list.Clear();
query.PageSize = 100; // return at most 100 results per request
while (connection.IMessages.Query(ref query, out temp))
  list.AddRange(temp);
list.AddRange(temp);
    Requirements

    Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

    See Also

    Reference

    IMessages Interface
    IMessages Members