OPCAE.NET Reference Manual
QueryEventAttributes(Int32,Int32[],String[],VarEnum[]) Method
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OPCAE.NET Namespace > OpcEventServer Class > QueryEventAttributes Method : QueryEventAttributes(Int32,Int32[],String[],VarEnum[]) Method

EventCategory
One of the Event Category codes returned from the QueryEventCategories function.
AttrIDs
Array of identifiers for vendor-specific event attributes associated with the event category and available from the server. These attribute IDs can be used in the event subscription interface to specify the information to be returned with an event notification.
AttrDescs
Array of strings for the text names or descriptions for each of the event attribute IDs. This array corresponds to the AttrIDs array.
AttrVarenumTypes
Array of VARTYPES identifying the data type of each of the event attributes. This array corresponds to the AttrIDs array.

Glossary Item Box

Using the EventCategories returned by the QueryEventCategories method, client application can invoke the QueryEventAttributes method to get information about the vendor-specific attributes the server can provide as part of an event notification for an event within the specified event category. Simple servers may not support any vendor-specific attributes for some or even all EventCategories. Attributes of event notifications are described in OPC AE specification section 2.5.2. Some possible vendor-specific attributes are included in Appendix C of the OPC AE specification.

Syntax

Visual Basic (Declaration) 
Public Overloads Function QueryEventAttributes( _
   ByVal EventCategory As Integer, _
   ByRef AttrIDs As Integer(), _
   ByRef AttrDescs As String(), _
   ByRef AttrVarenumTypes As VarEnum() _
) As Integer
C# 
public int QueryEventAttributes( 
   int EventCategory,
   out int[] AttrIDs,
   out string[] AttrDescs,
   out VarEnum[] AttrVarenumTypes
)

Parameters

EventCategory
One of the Event Category codes returned from the QueryEventCategories function.
AttrIDs
Array of identifiers for vendor-specific event attributes associated with the event category and available from the server. These attribute IDs can be used in the event subscription interface to specify the information to be returned with an event notification.
AttrDescs
Array of strings for the text names or descriptions for each of the event attribute IDs. This array corresponds to the AttrIDs array.
AttrVarenumTypes
Array of VARTYPES identifying the data type of each of the event attributes. This array corresponds to the AttrIDs array.

Return Value

HRESULTS error/success code.

Requirements

Target Platforms: Windows 7/8/10, Windows Server 2003/2008/2012/2016, .NET 4.x

See Also

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