IXMLDOMSelection::context Method

IXMLDOMSelection::get_context Method

Gets the node (subtree) that is applied to the selection.

Visual Basic Syntax

Set objXMLDOMNode = objXMLDOMSelection.context

C/C++ Syntax

HRESULT get_context(IXMLDOMNode ** ppNode);

Parameters

ppNode [out]

The subtree to apply the pattern to.

C/C++ Return Values

S_OK

Value returned if the method is successful.

S_FALSE

Value returned if the context is invalid.

E_INVALIDARG

Value returned if the input argument is Null.

Remarks

Because selectNodes can be called on any node type, context can also be assigned any node type. A node from a different document than the one that originally created this XMLDOMSelection object can also be specified as long as it has the same threading model. Calling context also resets the state of the node list so that nextNode starts over.

Example

The following Visual Basic example shows what the context of a selection contains when a query is executed and also that the selected set is reset when this property is changed:

Dim xmlDoc As New MSXML2.DOMDocument
Dim selection As MSXML2.IXMLDOMSelection

xmlDoc.loadXML ("<Customer>Microsoft</Customer>")
xmlDoc.setProperty "SelectionLanguage", "XPath"
Set selection = xmlDoc.selectNodes("//Customer")
MsgBox selection.context.xml

Selection.context.xml contains "<Customer>Amit</Customer>", selection.length = 1

xmlDoc.loadXML ("<new>none</new>")
MsgBox selection.context.xml

Selection.context.xml contains "<new>no-one</new>", selection.length = 0

---

IXMLDOMSelection::put_context Method

Specifies the node (subtree) to apply to the selection.

Visual Basic Syntax

objXMLDOMSelection.context = objXMLDOMNode

C/C++ Syntax

HRESULT putref_context(IXMLDOMNode * pNode);

Parameters

pNode [in]

The subtree to apply the pattern to.

C/C++ Return Values

S_OK

Value returned if the context is set successfully.

E_FAIL

Value returned if a node with a different threading model is provided.

Remarks

Because selectNodes can be called on any node type, context can also be assigned any node type. A node from a different document than the one that originally created this XMLDOMSelection object can also be specified as long as it has the same threading model. Calling context also resets the state of the node list so that nextNode starts over.

Example

The following C++ code example shows what the context property contains after selectNodes is executed.

BOOL DOMSelectionContextDemo()
{
   BOOL bResult = FALSE;
   short sResult = FALSE;
   IXMLDOMSelection *pIXMLDOMSelection=NULL;
   IXMLDOMNode *pIXMLDOMNode=NULL;
   IXMLDOMDocument2 *pIXMLDOMDocument2=NULL;
   HRESULT hr;
   BSTR bstrValue;

   try
   {
      hr=CoCreateInstance(CLSID_DOMDocument, NULL, CLSCTX_SERVER, 
         IID_IXMLDOMDocument2, (LPVOID*)(&pIXMLDOMDocument2));
      SUCCEEDED(hr) ? 0 : throw hr;

      if(pIXMLDOMDocument2)
      {
         hr=pIXMLDOMDocument2->put_async(VARIANT_FALSE);
         if(SUCCEEDED(hr))
         {
            hr=pIXMLDOMDocument2->load(_variant_t( 
               _T("d:\\inetpub\\wwwroot\\samplexml.xml")), &sResult);
            if(SUCCEEDED(hr) && (sResult==VARIANT_TRUE))
            {
               hr=pIXMLDOMDocument2->selectNodes( 
               _T("*/BOOK[TITLE='Cosmos']"),
               (IXMLDOMNodeList**)&pIXMLDOMSelection);
               if(SUCCEEDED(hr))
               {
                  if(SUCCEEDED(hr) && pIXMLDOMSelection)
                  {
                     hr=pIXMLDOMSelection->get_context(&pIXMLDOMNode);
                     if(SUCCEEDED(hr) && pIXMLDOMNode)
                     {
                        hr=pIXMLDOMNode->get_xml(&bstrValue);
                        if(SUCCEEDED(hr))
                           ::MessageBox(NULL, bstrValue, _T("Current 
                              Selection Context"), MB_OK);
                        bResult=TRUE;
                        RELEASE(pIXMLDOMNode);
                     }
                     RELEASE(pIXMLDOMSelection);
                  }
               }
            }
         }
         RELEASE(pIXMLDOMDocument2);
      }
   }
   catch(...)
   {
      CHECK_AND_RELEASE(pIXMLDOMNode);
      CHECK_AND_RELEASE(pIXMLDOMSelection);
      CHECK_AND_RELEASE(pIXMLDOMDocument2);
      DisplayErrorToUser();
   }
   return bResult;
}

d:\\inetpub\\wwwroot\\samplexml.xml

<?xml version='1.0'?>
<COLLECTION xmlns:dt="urn:schemas-microsoft-com:datatypes">
   <DATE dt:dt="datetime">1998-10-13T15:56:00</DATE>
   <BOOK>
      <TITLE>Cosmos</TITLE>
      <AUTHOR>Carl Sagan</AUTHOR>
      <PUBLISHER>Ballantine Books</PUBLISHER>
   </BOOK>
   <BOOK>
      <TITLE>Catwings</TITLE>
      <AUTHOR>Ursula K. Le Guin</AUTHOR>
      <PUBLISHER>Scholastic</PUBLISHER>
   </BOOK>
</COLLECTION>

Output (in a message box)

<?xml version='1.0'?>
<COLLECTION xmlns:dt="urn:schemas-microsoft-com:datatypes">
   <DATE dt:dt="datetime">1998-10-13T15:56:00</DATE>
   <BOOK>
      <TITLE>Cosmos</TITLE>
      <AUTHOR>Carl Sagan</AUTHOR>
      <PUBLISHER>Ballantine Books</PUBLISHER>
   </BOOK>
   <BOOK>
      <TITLE>Catwings</TITLE>
      <AUTHOR>Ursula K. Le Guin</AUTHOR>
      <PUBLISHER>Scholastic</PUBLISHER>
   </BOOK>
</COLLECTION>

See Also

IXMLDOMSelection Interface