NativeXml (10)：编辑

uses NativeXml; 
 
var xml: TNativeXml; 
 
const 
  xmlStr = '<?xml version="1.0" encoding="UTF-8"?>' + 
           '<List>' + 
           '<item ID="No.1" age="11">张三</item>' + 
           '<item ID="No.2" age="22">李四</item>' + 
           '<item ID="No.3" age="33">王五</item>' + 
           '</List>'; 
 
procedure TForm1.FormCreate(Sender: TObject); 
begin 
  xml := TNativeXml.Create(Self); 
  xml.XmlFormat := xfReadable; 
  xml.ReadFromString(xmlStr);     {!} 
  Memo1.Text := xml.WriteToString; 
end; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.1" age="11">张三</item> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
 
{插入、删除} 
procedure TForm1.Button2Click(Sender: TObject); 
begin 
  xml.ReadFromString(xmlStr); 
  xml.Root.NodeInsert(1, xml.NodeNewText('item', '赵六')); 
  xml.Root.NodeDelete(xml.Root.NodeCount - 1); 
  Memo1.Text := xml.WriteToString; 
end; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.1" age="11">张三</item> 
	<item>赵六</item> 
	<item ID="No.2" age="22">李四</item> 
</List> 
*****************************************} 
 
{移除} 
procedure TForm1.Button3Click(Sender: TObject); 
begin 
  xml.ReadFromString(xmlStr); 
  xml.Root.NodeRemove(xml.Root[0]); 
  Memo1.Text := xml.WriteToString; 
end; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
 
{交换} 
procedure TForm1.Button4Click(Sender: TObject); 
begin 
  xml.ReadFromString(xmlStr); 
  xml.Root.NodeExchange(0, 1); 
  Memo1.Text := xml.WriteToString; 
end; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.1" age="11">张三</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
 
{提取} 
procedure TForm1.Button5Click(Sender: TObject); 
var 
  node: TXmlNode; 
begin 
  xml.ReadFromString(xmlStr); 
  node := xml.Root.NodeExtract(xml.Root[1]); 
  Memo1.Text := node.WriteToString; 
  Memo1.Lines.Add('---------------------------------------'); 
  Memo1.Lines.Add(xml.WriteToString); 
end; 
{*************************************** 
	<item ID="No.2" age="22">李四</item> 
--------------------------------------- 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.1" age="11">张三</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
 
{获取位置} 
procedure TForm1.Button6Click(Sender: TObject); 
var 
  n1,n2: Integer; 
begin 
  xml.ReadFromString(xmlStr); 
 
  n1 := xml.Root.NodeIndexOf(xml.Root[xml.Root.NodeCount-1]); 
  ShowMessage(IntToStr(n1)); //2 
 
  n2 := xml.Root.NodeIndexOf(xml.Root[xml.Root.NodeCount]); 
  ShowMessage(IntToStr(n2)); //-1 
end; 
 
procedure TForm1.Button7Click(Sender: TObject); 
var 
  node: TXmlNode; 
begin 
  xml.ReadFromString(xmlStr); 
 
  node := xml.Root.NodeFindOrCreate('item'); 
  ShowMessage(node.WriteToString); //<item ID="No.1" age="11">张三</item> 
 
  node := xml.Root.NodeFindOrCreate('张三'); 
  ShowMessage(node.WriteToString); //<张三/> 
  Memo1.Text := xml.WriteToString; 
end; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.1" age="11">张三</item> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.3" age="33">王五</item> 
	<张三/> 
</List> 
*****************************************} 
 
procedure TForm1.Button8Click(Sender: TObject); 
var 
  node: TXmlNode; 
begin 
  xml.ReadFromString(xmlStr); 
  node := xml.Root[0]; 
  node.Clear; 
  Memo1.Text := xml.WriteToString; 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item/> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
  xml.Root.DeleteEmptyNodes; 
  Memo1.Lines.Add('---------------------------------------'); 
  Memo1.Lines.Add(xml.WriteToString); 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List> 
	<item ID="No.2" age="22">李四</item> 
	<item ID="No.3" age="33">王五</item> 
</List> 
*****************************************} 
  xml.Root.Clear; 
  Memo1.Lines.Add('---------------------------------------'); 
  Memo1.Lines.Add(xml.WriteToString); 
{*************************************** 
<?xml version="1.0" encoding="UTF-8"?> 
<List/> 
*****************************************} 
  xml.Clear; 
  Memo1.Lines.Add('---------------------------------------'); 
  Memo1.Lines.Add(xml.WriteToString); 
{*************************************** 
 
*****************************************}
end;