Pascal (Lazarus/Delphi)

XML Document References

See more XML Examples

This example demonstrates the fact that the entire XML document remains in memory if at least one node is referenced. (It does not need to be the root node.) 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;
  xB: TXml;

begin
  success := False;

  xml := TXml.Create;

  success := xml.LoadXml('<a><b>BBB</b><c>CCC</c></a>');

  WriteLn(xml.GetXml());

  //  We have the following XML stored in memory:

  //  	<?xml version="1.0" encoding="utf-8"?>
  //  	<a>
  //  	    <b>BBB</b>
  //  	    <c>CCC</c>
  //  	</a>

  //  Get a reference to the 1st child.
  xB := xml.GetChild(0);

  //  Re-load "xml" with an entirely new document:
  success := xml.LoadXml('<z><x>XXX</x></z>');

  //  What happens to xB?
  //  The answer is nothing.  xB still points ot the "b" node in the original document, and the entire
  //  original document remains in memory.  We now have two XML documents in memory.

  WriteLn(xB.GetXml());

  //  output is:

  //      <b>BBB</b>

  //  Make xB reference the root node of its document:
  xB.GetRoot2();
  WriteLn(xB.GetXml());

  //  You can see here that the entire original XML document is still available
  //  because at least one node in the XML is referenced by a variable.
  //  The output is:

  //      <?xml version="1.0" encoding="utf-8"?>
  //      <a>
  //          <b>BBB</b>
  //          <c>CCC</c>
  //      </a>

  //  We can also see that "xml" contains an entirely new XML document:
  WriteLn(xml.GetXml());

  //      <?xml version="1.0" encoding="utf-8"?>
  //      <z>
  //          <x>XXX</x>
  //      </z>
  //  

  xB.Free;


  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.