Choosing a Threading Model

 

There are two versions of the XML control.

rental model
The rental model version is designed for single-threaded access. To use the rental model control provided with MSXML 6.0, use the Microsoft.DOMDocument.6.0 progID.

free-threaded model
The free-threaded model version is designed for multiple thread access. To use the free-threaded control provided with MSXML 6.0, use the Microsoft.FreeThreadedDOMDocument.6.0 progID.

System_CAPS_ICON_note.jpg Note

In MSXML, "free-threaded" means ThreadingModel='Both', and cross-thread marshalling is supported.

If you plan for several threads to access your XML data from a single control, be sure to use the free-threaded control. If only one thread will access the XML data, use the rental model control for better performance.

The following is a sample global.asa file that creates session-level and application-level free-threaded versions of the XML control.

<SCRIPT LANGUAGE=VBScript RUNAT=Server>  
  Sub Session_OnStart  
    ON error RESUME next  
  
    SET Application("AppFXMLdoc") = _  
      server.CreateObject("Msxml2.FreeThreadedDOMDocument.6.0")  
    SET Session("SessFXMLdoc") = _  
      server.CreateObject("Msxml2.FreeThreadedDOMDocument.6.0")  
  End Sub  
  Sub Session_OnEnd  
    ON error RESUME next  
  
    SET Session("SessFXMLdoc") = nothing  
    SET Application("AppFXMLdoc") = nothing  
    Session("SessFXMLdoc") = empty  
    Application("AppFXMLdoc") = empty  
  End Sub  
</SCRIPT>  

Scripts accessing the Session and Application objects will be able to simultaneously access the AppFXMLdoc and SessFXMLdoc objects.

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