Pascal (Lazarus/Delphi)

Traverse Direct Children via FirstChild / NextSibling, or LastChild / PreviousSibling

See more XML Examples

Demonstrates some ways to iterate over direct child nodes using the FirstChild / NextSibling and LastChild / PreviousSibling methods.

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

<root>
    <fruit color="red">apple</fruit>
    <fruit color="green">pear</fruit>
    <veg color="orange">carrot</veg>
    <meat animal="cow">beef</meat>
    <xyz>
        <fruit color="blue">blueberry</fruit>
        <veg color="green">broccoli</veg>
    </xyz>
    <fruit color="purple">grape</fruit>
    <cheese color="yellow">cheddar</cheese>
</root>

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Xml;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  xml: TXml;
  child: TXml;
  nextSibling: TXml;
  prevSibling: TXml;
  bContinue: Boolean;

begin
  success := False;

  xml := TXml.Create;

  success := xml.LoadXmlFile('qa_data/xml/fruit.xml');
  if (success <> True) then
    begin
      WriteLn(xml.LastErrorText);
      Exit;
    end;

  //  Iterate over the direct children by using FirstChild / NextSibling
  child := xml.FirstChild();
  bContinue := xml.LastMethodSuccess;
  while (bContinue = True) do
    begin
      WriteLn(child.Tag + ' : ' + child.Content);
      nextSibling := child.NextSibling();
      bContinue := child.LastMethodSuccess;
      child.Free;
      child := nextSibling;
    end;

  WriteLn('-----');

  //  Do the same, but with FirstChild2 / NextSibling2 to avoid
  //  creating so many XML object instances:
  success := xml.FirstChild2();
  while success = True do
    begin
      WriteLn(xml.Tag + ' : ' + xml.Content);
      success := xml.NextSibling2();
    end;

  //  Revert back up to the parent:
  success := xml.GetParent2();

  WriteLn('-----');

  //  Iterate in reverse order using LastChild / PreviousSibling
  child := xml.LastChild();
  bContinue := xml.LastMethodSuccess;
  while (bContinue = True) do
    begin
      WriteLn(child.Tag + ' : ' + child.Content);
      prevSibling := child.PreviousSibling();
      bContinue := child.LastMethodSuccess;
      child.Free;
      child := prevSibling;
    end;

  WriteLn('-----');

  //  Do the same, but with LastChild2 / PreviousSibling2 to avoid
  //  creating so many XML object instances:
  success := xml.LastChild2();
  while success = True do
    begin
      WriteLn(xml.Tag + ' : ' + xml.Content);
      success := xml.PreviousSibling2();
    end;

  //  Revert back up to the parent:
  success := xml.GetParent2();


  xml.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.