Delphi中解析Xml的控件-SimDesign NativeXml
正在学习，感觉应用很方便。无源代码的版本还是免费的。
SimDesign.NativeXml是一个delphi和bcb的XML控件，包含一个精巧的Delphi XML执行，使你能在程序中读写XML文档。
http://www.simdesign.nl/xml.html
网上有一个利用SimDesign.NativeXml生成XML的例子。
一个更加强大易用的XML库 -- NativeXML
原来一直使用Delphi自带的TXMLDocument类来进行XML文件的读写，虽然麻烦了一点，但功能上来说还不错。只是有一个地方让我实在不舒服 - 每次创建TXMLDocument类实例的时候必须传入TComponent对象，这就意味着，如果我把对XML文件的读写封装到一个类里面，那么在创建这个自定义类的时候就必须也传入TComponent对象。
我尝试过很多方法，但是都无法避免，最后试着上网找了找，于是就找到了NativeXML这个库。
下载之后马上打开Demo看了看，cool，创建TNativeXML的时候只需要传入xml文件路径就可以，再往下看就让我开始惊喜了。它已经把大多数操作都封装好了，而且还具有把任意对象序列化的能力。
比如，你能把整个Form通过 TsdXmlObjectWriter = class(TPersistent) 类存入一个XML文件，下次再读取。这样使得远程传输对象变得很简单了。
下面就是一个使用NativeXML库的例子：
目标XML结构:
<bookshift>
<book author = "test_author">
<date>2000-01-01</date>
</book>
</bookshift>
delphi 代码:
procedure WriteTest;
var
xml : TNativeXML;
n_bs : TXMLNode;
begin
//
建立根节点
xml := TNativeXml.CreateName('bookshift');
xml.EncodingString := 'GB2312';
//
输出风格为易读
xml.XmlFormat := xfReadable;
//
建立Book节点
n_bs := xml.Root.NodeNew('book');
//
写入Book节点的属性
n_bs.WriteAttribuiteString('author','test_author');
//
建立Book节点下属date节点并写入值
n_bs.WriteString('date','2000-01-01');
xml.SaveToFile('test.xml');
end;
打开test.xml文件看看吧，和上面的格式一摸一样。很简单吧，我用这个库重写了原来的XML访问类，大约节省了40%的代码量。SimDesign.NativeXml自带的读取XML文档的例子。
注意：以下代码转贴时有误，未经测试
{ Example 3
Demo unit that shows how to import XML data into record structure.
It is a "real-life" example written for one of our customers.
It shows how to use the method "NodesByName", creating a temporary
list of node elements with the same name.
It uses NativeXml to handle the conversion.
This was the original request for the conversion:
" Data should be placed in a record with this structure:
type
FieldRecord= record
FieldId: String;
FieldReq: String;
FieldType: String;
FieldCap: String;
DependField: String;
MetaType: String;
MetaData: String;
End;
De enums and the hashtables must be stored in MetaData,
in the following manner:
Enums: enumvalue
_id1 + ',' + enum_caption1 + ";" + enumvalue
_id2 + ',' + enum_caption2 + ";" + etc.....
HashTable: codeid1 + ',' + hashdata1 + ';' +
codeid2 + ',' + hashdata2 + etc......
If there's no MetaData the field should remain empty. "
Author: Nils Haeck, Simdesign
http://www.simdesign.nl
More info at:
http://www.simdesign.nl/xml.html
}
unit Example3Main;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, NativeXml, ComCtrls;
type
// This is the record structure
FieldRecord= record
FieldId: String;
FieldReq: String;
FieldType: String;
FieldCap: String;
DependField: String;
MetaType: String;
MetaData: String;
end;
//////////////////////////////////////////////////////////////////
TForm1 = class(TForm)
mmXML: TMemo;
btnImportXML: TButton;
lbStatus: TLabel;
Label1: TLabel;
lvTable: TListView;
Label2: TLabel;
Label3: TLabel;
procedure btnImportXMLClick(Sender: TObject);
procedure lvTableData(Sender: TObject; Item: TListItem);
private
public
Fields: array of FieldRecord; // This is a dynamic array of records
procedure LoadFieldFromNode(var AField: FieldRecord; ANode: TXmlNode);
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.btnImportXMLClick(Sender: TObject);
// Read XML from TMemo and convert into record structure
var
i: integer;
ADoc: TNativeXml;
ANode: TXmlNode;
AList: TList;
begin
ADoc := TNativeXml.Create;
try
// Read from memo
ADoc.ReadFromString(mmXML.Text);
// A temporary list to hold references to the record elements
AList := TList.Create;
try
ANode := ADoc.Root.NodeByName('fields');
if not assigned(ANode) then exit;
// List of nodes that are named "field"
ANode.NodesByName('field', AList);
// Set dynamic array length
SetLength(Fields, AList.Count);
// Import each element
for i := 0 to AList.Count - 1 do
LoadFieldFromNode(Fields[I], AList[I]);
// Show table
lvTable.Items.Count := AList.Count;
lvTable.Invalidate;
// Status
lbStatus.Caption := Format('Imported %d records', [AList.Count]);
finally
AList.Free;
end;
finally
ADoc.Free;
end;
end;
procedure TForm1.LoadFieldFromNode(var AField: FieldRecord;
ANode: TXmlNode);
// Load one field from the XML element ANode
var
i: integer;
AMeta: TXmlNode;
AEnum: TXmlNode;
AList: TList;
begin
with AField, ANode do begin
// Initialize record
FillChar(AField, SizeOf(AField), 0);
// The flat data
FieldId := AttributeByName['id'];
FieldReq := AttributeByName['required'];
FieldType := AttributeByName['type'];
FieldCap := ReadString('caption');
DependField := AttributeByName['dependsfield'];
// Meta data
AMeta := NodeByName('metadata');
if assigned(AMeta) then
with AMeta do
begin
MetaType := AttributeByName['type'];
///////////////////////////////////////////////////////////////
// List that holds enumeration
AList := TList.Create;
try
// "enum" metadata
if MetaType = 'enum' then
begin
AEnum := NodeByName('enumeration');
if assigned(AEnum) then
AEnum.NodesByName('enumvalue', AList);
// all enumeration values
for i := 0 to AList.Count - 1 do
with TXmlNode(AList[I) do
MetaData := MetaData +
AttributeByName['id'] + ',' + ReadString('caption') + ';';
end;
// "hashtable" metadata
if MetaType = 'hashtable' then
begin
AEnum := NodeByName('hashtable');
if assigned(AEnum) then
AEnum.NodesByName('code', AList);
// all enumeration values
for i := 0 to AList.Count - 1 do with TXmlNode(AList[I]) do
MetaData := MetaData +
AttributeByName['id'] + ',' + valueAsString + ';';
end;
finally
AList.Free;
end;
end;
end;
end;
procedure TForm1.lvTableData(Sender: TObject; Item: TListItem);
// Add data to each item in the listview. We use the listview with OwnerData
begin
if (Item.Index >= 0) and (Item.Index < Length(Fields)) then
begin
with Fields[Item.Index] do
begin
Item.Caption := FieldID;
Item.SubItems.Add(FieldReq);
Item.SubItems.Add(FieldType);
Item.SubItems.Add(FieldCap);
Item.SubItems.Add(DependField);
Item.SubItems.Add(MetaType);
Item.SubItems.Add(MetaData);
end;
end;
end;
end.