(Delphi DLL) 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>

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX 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
xml: HCkXml;
xyz: HCkXml;
success: Boolean;

begin
xml := CkXml_Create();

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

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

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

// 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 := CkXml_LoadXmlFile(xml,'fruit.xml');

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

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

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

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

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

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

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

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

// 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(CkXml_getTreeId(xyz)));
Memo1.Lines.Add('xml TreeId = ' + IntToStr(CkXml_getTreeId(xml)));

CkXml_Dispose(xyz);

CkXml_Dispose(xml);

end;