Share via

IXMLDOMNode::replaceChild

  • Article

banner art

Previous Next

IXMLDOMNode::replaceChild

The replaceChild method replaces the specified old child node with the supplied new child node.

Syntax

  HRESULT replaceChild(
 IXMLDOMNode* pNewChild, 
 IXMLDOMNode* pOldChild, 
 IXMLDOMNode** ppOutOldChild
);

Parameters

pNewChild

[in] Pointer to an IXMLDOMNode interface containing the address of the new child that is to replace the old child. If this parameter is NULL, pOldChild is removed without a replacement.

pOldChild

[in] Pointer to an IXMLDOMNode interface containing the address of the old child that is to be replaced by the new child.

ppOutOldChild

[out] Pointer to a pointer to an IXMLDOMNode interface containing the old child that is replaced. This method calls AddRef internally. To avoid memory leaks, you must call Release when you are finished using the interface.

Return Values

If the method succeeds, it returns S_OK. If it fails, it returns an HRESULT error code.

Remarks

When replacing an old child node with a new child node, the new child must be a valid child type for the existing parent node. The following tables list which child node types are valid and not valid for the parent node types specified.

The following table lists possible child node types for the parent node type NODE_ATTRIBUTE.

Child node type Description
NODE_ATTRIBUTE
NODE_COMMENT
NODE_ELEMENT		 Not valid. Returns an error. These node types cannot be children of an attribute.
NODE_PROCESSING_INSTRUCTION Not valid. Returns an error. This node type either cannot be a child of an attribute node or it is read-only.
NODE_TEXT Replaces the specified pOldChild with the supplied pNewChild and returns pOldChild.

The following table lists possible child node types for the parent node type NODE_DOCUMENT.

Child node type Description
NODE_ATTRIBUTE
NODE_DOCUMENT
NODE_TEXT		 Not valid. Returns an error. These nodes cannot be children of a document node.
NODE_COMMENT
NODE_PROCESSING_INSTRUCTION		 Replaces the specified pOldChild with the supplied pNewChild and returns pOldChild.
NODE_ELEMENT Replaces pOldChild with pNewChild and returns pOldChild. By definition, an XML document (the document node) can have only a single child element. Therefore, an error is returned if the document node already has a child element.

The following table lists possible child node types for the parent node type NODE_ELEMENT.

Child node type Description
NODE_ATTRIBUTE
NODE_DOCUMENT		 Not valid. Returns an error. These node types cannot be children of an element node.
NODE_COMMENT
NODE_ELEMENT
NODE_PROCESSING_INSTRUCTION
NODE_TEXT		 Replaces the specified pOldChild with pNewChild and returns pOldChild.

Example Code

The following example retrieves a pointer to an IXMLDOMNode interface, and replaces the specified child node with a new node.

#include "wmsserver.h"
#include <atlbase.h> // Includes CComVariant and CComBSTR.

// Declare variables.
IWMSServer*         pServer;
IXMLDOMDocument*    pPlaylist;
IXMLDOMElement*     pXMLElement;
IXMLDOMElement*     pXMLElementNew;
IXMLDOMNodeList*    pXMLNodeList;
IXMLDOMNode*        pXMLNodeCur;
IXMLDOMNode*        pXMLNodeRpl;
IXMLDOMNode*        pXMLNodeOld;

HRESULT             hr;
VARIANT_BOOL        bIsSuccessful;
CComVariant         varFile;
CComBSTR            bstrName;

// Initialize the COM library and retrieve a pointer
// to an IWMSServer interface.
hr = CoInitialize(NULL);
hr = CoCreateInstance(CLSID_WMSServer, NULL, CLSCTX_ALL, 
       IID_IWMSServer, (void**)&pServer);
if (FAILED(hr)) goto EXIT;

// Create the playlist object.
hr = pServer->CreatePlaylist(&pPlaylist);

// Load a sample playlist file.
varFile = "c:\\wmpub\\wmroot\\simple.wsx";
hr = pPlaylist->load(varFile, &bIsSuccessful);
if (FAILED(hr)) goto EXIT;

if (bIsSuccessful)
{
    // Retrieve a pointer to an IXMLDOMElement interface.
    hr = pPlaylist->get_documentElement(&pXMLElement);
    if (FAILED(hr)) goto EXIT;

    // Create a new element.
    bstrName = "seq";
    hr = pPlaylist->createElement(bstrName, &pXMLElementNew);
    if (FAILED(hr)) goto EXIT;

    // Retrieve a list of child nodes.
    hr = pXMLElement->get_childNodes(&pXMLNodeList);
    if (FAILED(hr)) goto EXIT;

    // Retrieve the second child node.
    hr = pXMLNodeList->get_item(1, &pXMLNodeCur);
    if (FAILED(hr)) goto EXIT;

    // Retrieve a list of child nodes from the current node.
    hr = pXMLNodeCur->get_childNodes(&pXMLNodeList);
    if (FAILED(hr)) goto EXIT;

    // Retrieve the first child of the current node.
    hr = pXMLNodeList->get_item(0, &pXMLNodeRpl);
    if (FAILED(hr)) goto EXIT;

    // Replace the child of the current node with
    // the newly created node.
    hr = pXMLNodeCur->replaceChild(pXMLElementNew, pXMLNodeRpl,
                                   &pXMLNodeOld);
    if (FAILED(hr)) goto EXIT;
}

EXIT:
    // TODO: Release temporary COM objects and uninitialize COM.

Requirements

Header: wmsserver.h.

Library: WMSServerTypeLib.dll.

Platform: Windows Server 2003 family, Windows Server 2008 family.

See Also

Previous Next