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Historian SDK

TABLE OF CONTENTS

ValueSelector Property (HistoryQueryResult)

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Gets or sets the column to return for specified analog summary tags in the four basic retrieval modes: DELTA, FULL, CYCLIC, and INTERPOLATED.

Syntax

'Declaration
 
Public Property ValueSelector As String
'Usage
 
Dim instance As HistoryQueryResult
Dim value As String
 
instance.ValueSelector = value
 
value = instance.ValueSelector
public string ValueSelector {get; set;}
public:
property String^ ValueSelector {
   String^ get();
   void set (    String^ value);
}

Property Value

Valid values are AUTO (the default in all modes if not overridden), MINIMUM or MIN, MAXIMUM or MAX, FIRST, LAST, AVERAGE or AVG, INTEGRAL, and STDDEV or STANDDEVIATION.

Remarks

The default AUTO setting returns the Last attribute in the Value column (which makes it accessible in the WideHistory table). You can only override the selector for the basic retrieval modes. FIRST, LAST, MIN, and MAX each have their own timestamp that will be used for the time part of the VTQ. AVG, INTEGRAL and STDDEV represent values that hold for the entire cycle so the summary period start time will be used for the time part of a VTQ.

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

HistoryQueryResult Class
HistoryQueryResult Members

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