Visual FoxPro

XML Tree Traversal Order for Search* Methods

See more XML Examples

The Chilkat XML API provides a number of Search* methods for locating XML nodes based on criteria. These methods traverse an XML document in a breadth-first order. (See Breadth-First Search).

The XML document used in this example has the following tree structure:

The nodes are traversed in the order: A, B, C, D, E, F, G, H, I, J, K.

The input XML, available at http://www.chilkatsoft.com/data/searchOrder.xml, is this:

<a>crocodileA
    <b>crocodileB
        <d>crocodileD</d>
        <e>crocodileE
            <h>crocodileH</h>
            <i>crocodileI</i>
        </e>
    </b>
    <c>crocodileC
        <f>crocodileF</f>
        <g>crocodileG
            <j>crocodileJ</j>
            <k>crocodileK</k>
        </g>
    </c>
</a>

Visual FoxPro

LOCAL lnSuccess
LOCAL loXml
LOCAL loXBeginAfter
LOCAL loXFound

lnSuccess = 0

loXml = CreateObject('Chilkat.Xml')

* The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
lnSuccess = loXml.LoadXmlFile("searchOrder.xml")
IF (lnSuccess <> 1) THEN
    ? loXml.LastErrorText
    RELEASE loXml
    CANCEL
ENDIF

* IMPORTANT:  The following loop for iterating over all 
* matching nodes performs reasonably well for small to 
* mid-size XML documents or sub-trees.  Performance
* can be poor when the sub-tree contains many thousands
* of nodes (or more).

* NOTE:  The search is always rooted at the calling node.
* In this example, it happens to also be the root node of the entire
* XML document.  Searches can be performed on sub-trees
* within the document by calling the Search* method from
* the root node of a sub-tree.

* Demonstrate the breadth-first traversal:
loXBeginAfter = loXml.GetSelf()
loXFound = loXml.SearchAllForContent(loXBeginAfter,"*croc*")
DO WHILE (loXml.LastMethodSuccess = 1)

    ? loXFound.Tag

    RELEASE loXBeginAfter
    loXBeginAfter = loXFound
    loXFound = loXml.SearchAllForContent(loXBeginAfter,"*croc*")
ENDDO

RELEASE loXBeginAfter

RELEASE loXml