(Delphi) XML Tree Traversal Order for Search* Methods

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>

Download Chilkat XML ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATXMLLib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
xml: CHILKATXMLLib_TLB.IChilkatXml;
xBeginAfter: CHILKATXMLLib_TLB.IChilkatXml;
xFound: CHILKATXMLLib_TLB.IChilkatXml;
success: Integer;

begin
xml := TChilkatXml.Create(Self).ControlInterface;

//  The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
success := xml.LoadXmlFile('searchOrder.xml');
if (success <> 1) then
  begin
    Memo1.Lines.Add(xml.LastErrorText);
    Exit;
  end;

//  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:
xBeginAfter := nil;
xFound := xml.SearchAllForContent(xBeginAfter,'*croc*');
while not (xFound = nil ) do
  begin

    Memo1.Lines.Add(xFound.Tag);

    xBeginAfter := xFound;
    xFound := xml.SearchAllForContent(xBeginAfter,'*croc*');
  end;


end;