Delphi DLL

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>

Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Xml;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
xml: HCkXml;
xBeginAfter: HCkXml;
xFound: HCkXml;

begin
success := False;

xml := CkXml_Create();

// The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
success := CkXml_LoadXmlFile(xml,'searchOrder.xml');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkXml__lastErrorText(xml));
    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 := CkXml_GetSelf(xml);
xFound := CkXml_SearchAllForContent(xml,xBeginAfter,'*croc*');
while (CkXml_getLastMethodSuccess(xml) = True) do
  begin

    Memo1.Lines.Add(CkXml__tag(xFound));

    CkXml_Dispose(xBeginAfter);
    xBeginAfter := xFound;
    xFound := CkXml_SearchAllForContent(xml,xBeginAfter,'*croc*');
  end;

CkXml_Dispose(xBeginAfter);

CkXml_Dispose(xml);

end;