Delphi 中的 XMLDocument 类详解(14) 遍历 XML 文件

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, xmldom, XMLIntf, msxmldom, XMLDoc, StdCtrls;

type
  TForm1 = class(TForm)
    XMLDocument1: TXMLDocument;
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


//读取 xml 的函数
{
  功能1: 传入一个节点参数, 返回节点及其包含的所有内容;
  功能2: 排除了空节点.
}
function ReadXml(node: IXMLNode): string;
var
  nodeList,attrList: IXMLNodeList;
  str,strName,strValue: string;
  i: Integer;
begin
  Result := '';
  if not node.HasChildNodes then Exit;

  attrList := node.AttributeNodes;      {根节点的属性列表}
  nodeList := node.ChildNodes;          {根节点下的子节点列表}

  str := '<' + node.NodeName;

  {先读取属性}
  for i := 0 to attrList.Count - 1 do
  begin
    strName := attrList[i].NodeName;
    strValue := attrList[i].NodeValue;
    str := str + ' ' + strName + '=' + AnsiQuotedStr(strValue, '"');
  end;
  str := str + '>' + sLineBreak; {sLineBreak 是常量, 相当于 #13#10}

  {读取子节点}
  for i := 0 to nodeList.Count - 1 do
  begin
    strName := nodeList[i].NodeName;
    if nodeList[i].IsTextElement then
    begin
      strValue := nodeList[i].NodeValue;
      str := str + '<' + strName + '>' + strValue + '</' + strName + '>' + sLineBreak;
    end else if nodeList[i].HasChildNodes then
    begin
      str := str + ReadXml(nodeList[i]);               {这是最关键的递归调用}
      str := str + '</' + strName + '>' + sLineBreak;  {封口}
    end;
  end;

  str := str + '</' + node.NodeName + '>'; {封口}

  Result := str;
end;


//调用测试(1):
procedure TForm1.Button1Click(Sender: TObject);
var
  str,s1,s2: string;
begin
  XMLDocument1.LoadFromFile('c:\temp\test.xml');
  {必须用万一提供的 xml 测试文件, 才能有相同的返回值}


  {读取文件头}
  s1 := AnsiQuotedStr(XMLDocument1.Version, '"');  {读出版本, 并添加双引号}
  s2 := AnsiQuotedStr(XMLDocument1.Encoding, '"'); {读出字符集, 并添加双引号}
  str := Format('<?xml version=%s encoding=%s?>',[s1,s2]); {这就是文件头了}

  str := str + sLineBreak + ReadXml(XMLDocument1.DocumentElement);

  ShowMessage(str); {返回 xml 包含问头在内的所有内容}
end;


//调用测试(2)
procedure TForm1.Button2Click(Sender: TObject);
var
  str: string;
  node: IXMLNode;
begin
  XMLDocument1.LoadFromFile('c:\temp\test.xml');

  node := XMLDocument1.DocumentElement.ChildNodes[0];

  str := ReadXml(node);

  ShowMessage(str); {返回返回根节点下第一个子节点的所有内容}
end;

end.