(Delphi) Removing / Deleting Child Nodes from XML

Demonstrates various methods for removing child nodes from an XML document.

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>

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;
xyz: CHILKATXMLLib_TLB.IChilkatXml;
success: Integer;

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

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

//  The RemoveChild method removes (discards) all direct
//  children having the specified tag:
xml.RemoveChild('fruit');

//  Show the resulting XML:
Memo1.Lines.Add('Result with all direct children having a tag equal to "fruit" removed:');
Memo1.Lines.Add(xml.GetXml());

//  The XML with the "fruit" direct children removed is shown below:
//  Notice that the "fruit" node beneath "xyz" was not removed.
//  This correct because it was not a direct child of the calling node.
//  
<root>
    <veg color="orange">carrot</veg>
    <meat animal="cow">beef</meat>
    <xyz>
        <fruit color="blue">blueberry</fruit>
        <veg color="green">broccoli</veg>
    </xyz>
    <cheese color="yellow">cheddar</cheese>
</root>


//  --------------------------------------------------------------------------
//  Restore the original XML:
success := xml.LoadXmlFile('fruit.xml');

//  The RemoveChildWithContent method removes the child
//  having the exact content specified, regardless of the tag.
//  For example:
xml.RemoveChildWithContent('pear');

//  Show the resulting XML:
Memo1.Lines.Add('Result with the node containing "pear" removed:');
Memo1.Lines.Add(xml.GetXml());

//  --------------------------------------------------------------------------
//  Restore the original XML:
success := xml.LoadXmlFile('fruit.xml');

//  The RemoveChildByIndex method removes the Nth direct
//  child.  Indexing begins at 0.  The "xyz" child is at index 4:
xml.RemoveChildByIndex(4);

//  Show the resulting XML:
//  Notice that the entire "xyz" subtree is removed.
Memo1.Lines.Add('Result with the node at index 4 removed:');
Memo1.Lines.Add(xml.GetXml());

//  --------------------------------------------------------------------------
//  Restore the original XML:
success := xml.LoadXmlFile('fruit.xml');

//  Navigate to the node with tag "xyz"
xyz := xml.FindChild('xyz');

//  Remove the "xyz" subtree making it it's own XML document
//  with the "xyz" node at the root:
xyz.RemoveFromTree();

//  Show both XML documents:
Memo1.Lines.Add(xyz.GetXml());
Memo1.Lines.Add(xml.GetXml());

//  Also, the TreeId property is an integer value assigned
//  to nodes in an XML document.  All nodes belonging to
//  the same XML document will have the same TreeId.
//  Notice that the "xyz" node now has a different TreeId:
Memo1.Lines.Add('xyz TreeId = ' + IntToStr(xyz.TreeId));
Memo1.Lines.Add('xml TreeId = ' + IntToStr(xml.TreeId));


end;