当操作多个xml文档时，并且每个文档都有自己定义的节点属名，这种在程序中写死的调用方式就很不灵活了。
delphi6.0起提供了把xml当数据库访问控件，使上述问题迎刃而解。
首先要用到XML映象器 xml mapper
XML
Mapper 使用示例
首先，将下列文件存为u8格式文件，文件名字为userxml.xml
<?xml version="1.0"
encoding="UTF-8" ?>
- <user-watcher>
- <users>
<id>900</id>
<name>111</name>
<sex>男</sex>
<birth>1979-8-7</birth>
<tel>1236547890</tel>
<addr>tom 大街 8 号</addr>
<postcode>100018</postcode>
<email>tom@888.com</email>
</users>
- <users>
<id>9007</id>
<name>tom</name>
<sex>男</sex>
<birth>1979-8-7</birth>
<tel>1236547890</tel>
<addr>tom 大街 8 号</addr>
<postcode>100018</postcode>
<email>tom@888.com</email>
</users>
- <users>
<id>90077</id>
<name>tom</name>
<sex>男</sex>
<birth>1979-8-7</birth>
<tel>1236547890</tel>
<addr>tom 大街 8 号</addr>
<postcode>100018</postcode>
<email>tom@888.com</email>
</users>
- <users>
<id>900777</id>
<name>tom</name>
<sex>男</sex>
<birth>1979-8-7</birth>
<tel>1236547890</tel>
<addr>tom 大街 8 号</addr>
<postcode>100018</postcode>
<email>tom@888.com</email>
</users>
- <users>
<id>800</id>
<name>tom</name>
<sex>男</sex>
<birth>1979-8-7</birth>
<tel>1236547890</tel>
<addr>tom 大街 8 号</addr>
<postcode>100018</postcode>
<email>tom@888.com</email>
</users>
- <users>
<id>11</id>
<name>22</name>
<sex>33</sex>
<birth>44</birth>
<tel>55</tel>
<addr>66</addr>
<postcode>77</postcode>
<email>7777777777777</email>
</users>
</user-watcher>
1,delphi6 tools 启动xmlmapper
2,file open
userxml.xml
3,在最左面树状列里面单击鼠标右键，选择 select all
4,选择xml to datapacket
5,create,datapacket from xml
6,点击create and test transformation
7,file,save,transformation,文件名为：ToDp.xtr
以上是xml到db的过程，只完成了一半，现在还要db
to xml
1,如果没有打开xml mapper，则重复上面1,2,3操作，如果是接着上面操作，则
2,选择datapacket to
xml
3,create,datapacket from xml
4,点击create and test transformation
5,file,save,transformation,文件名为：ToDpIns.xtr
操作完毕，特别提示，xtr不支持带有中文的注释的xml,所以建议删除注释
TXMLTransformProvider组件通过*.xtr文件将原始XML文件转换到ClientDataSet。
举例来说，在Delphi
6的主窗体上安放一个TXMLTransformProvider(在Data Access标签里)。
将TransformRead属性的TransformationFile子属性设为ToDp.xtr作为数据源。
将XMLDataFile设为userxml.xml文件。
然后安放一个ClientDataSet组件，将它的ProviderName属性设为XMLTransformProvider。
现在可以激活ClientDataSet组件了，它将由XMLTransformProvider提供的数据转换过来。
它的PacketRecords属性值缺省为-1，表示转换全部XML文件。
要显示数据，我们再加入DataSource和DBGrid组件。
将DataSource指向ClientDataSet，DBGrid指向DataSource，就象我们通常使用得那样。
现在可以象使用数据库数据那样使用XML文件里的数据了。
如果对数据进行了修改，可以调用ClientDataSet.ApplyUpdates方法将改动的数据存回XML文件。
但是这样做是不够的。我们还得启动XML映象器，将创建方式由"XML to Datapacket"改为"Datapacket to XML"。
这时如果按下"Create and Test Transformation"键，然后将转换结果存为ToDpIns.xtr文件。
现在，将TXMLTransformationProvider的TransformationWrite属性中的子属性TransformationFile设为ToDpIns.xtr文件。
最后在主窗体的OnClose事件中加上存盘指令：
ClientDataSet1.ApplyUpdates(-1)
程序退出之前会将作出的数据修改存回XML文件。
示例源程序：
unit XMLProvider;
//----------------------------------------------------------------------------
//本实例演示
//1，XML mapper 的简单使用
//2，XML 当作数据库操作的填加，删除，修改（替换），保存等操作
//作者：cactus123456@hotmail.com
//日期：2005.11.15
//版本：1.0
//----------------------------------------------------------------------------
interface
uses
Windows, Messages, SysUtils, Variants, Classes,
Graphics, Controls, Forms,
Dialogs, StdCtrls, Grids, DBGrids, ExtCtrls,
DB, DBClient, Provider, xmldom,
Xmlxform, DBCtrls;
type
TForm1 =
class(TForm)
Panel1: TPanel;
Label1: TLabel;
DBGrid1:
TDBGrid;
Button1: TButton;
Button2: TButton;
Memo1:
TMemo;
ClientDataSet1: TClientDataSet;
DataSource1: TDataSource;
Label3: TLabel;
XMLTransformProvider1: TXMLTransformProvider;
Button3: TButton;
Edit1: TEdit;
DBNavigator1:
TDBNavigator;
procedure Button1Click(Sender: TObject);
procedure
Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
private
{ Private declarations }
public
{ Public
declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
begin
ClientDataSet1.Active:= false;
ClientDataSet1.Active:= true;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ClientDataSet1.ApplyUpdates(1);
end;
procedure
TForm1.Button3Click(Sender: TObject);
begin
ClientDataSet1.SaveToFile(Edit1.Text, dfXML);
end;
end.
对应的form文件
object Form1: TForm1
Left = 299
Top = 141
AutoScroll =
False
Caption = 'TXMLTransformProvider'
ClientHeight = 519
ClientWidth = 646
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -10
Font.Name = 'MS
Sans Serif'
Font.Style = []
OldCreateOrder = False
Position =
poDesktopCenter
PixelsPerInch = 96
TextHeight = 13
object
Panel1: TPanel
Left = 0
Top = 0
Width = 646
Height = 519
Align = alClient
TabOrder = 0
object
Label1: TLabel
Left = 20
Top = 43
Width = 280
Height = 16
HelpType = htKeyword
Caption = 'Views
and updates the Xml-Document ''pos.xml'''
Font.Charset =
DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -15
Font.Name = 'MS Sans Serif'
Font.Style = []
ParentFont = False
end
object Label3: TLabel
Left = 20
Top = 13
Width = 340
Height = 20
HelpType = htKeyword
Caption = 'Example of using TXMLTransformProvider
'
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -16
Font.Name = 'MS Sans Serif'
Font.Style = [fsBold]
ParentFont = False
end
object
DBGrid1: TDBGrid
Left = 16
Top = 330
Width = 609
Height = 169
DataSource = DataSource1
TabOrder = 0
TitleFont.Charset = DEFAULT_CHARSET
TitleFont.Color =
clWindowText
TitleFont.Height = -10
TitleFont.Name = 'MS
Sans Serif'
TitleFont.Style = []
end
object Button1:
TButton
Left = 15
Top = 291
Width = 90
Height = 30
Caption = 'Get data'
TabOrder = 1
OnClick = Button1Click
end
object Button2: TButton
Left = 126
Top = 291
Width = 121
Height = 30
Caption = 'Apply Updates'
TabOrder = 2
OnClick =
Button2Click
end
object Memo1: TMemo
Left = 16
Top = 66
Width = 609
Height = 183
Lines.Strings = (
'TXMLTransformProvider transforms a generic
xml-document into a'
'Datapacket.'
'Data aware
controls such as DBGrids, XMLBroker( Internet Expres' +
's) etc.
'
'can now be used to display, browse and update the data from
the' +
'se documents.'
'The updated data can then be
resolved back to the original xml-d' +
'ocument.'
'TXMLTransformProvider description:'
'XMLDataFile:'
'Points to the generic xml-file '
'TransformRead.TransformationFile:'
'Points to the transformation
file (''.xtr'') for ''Xml to Datapack' +
'et''.'
'Created by ''XmlMapper''.'
'TransformWrite.TransformationFile:'
'Points to the transformation file for ''Datapacket to Xml''.'
'CacheData :'
'Set property to cache the ''transformed''
Xml file.'
'Events:'
'TransformRead.OnTranslate'
'TransformWrite.OnTranslate:'
'Used to intercept and
translate field-values marked as ''Userdefi' +
'ned'' in
XmlMapper.'
'Note: When writing back updates to the xml-file the
file is recr' +
'eated and '
'rewritten, so when
creating the transformations all data-fields ' +
'should be mapped
'
'to avoid data-loss.'
'Note: As is the case with
ClientDatasets, this technology limits' +
' data-size'
'to available memory and is not intended for ''huge'' xml-files.')
ScrollBars = ssBoth
TabOrder = 3
end
object Button3:
TButton
Left = 352
Top = 291
Width = 65
Height = 30
Caption = 'Save'
TabOrder = 4
OnClick
= Button3Click
end
object Edit1: TEdit
Left = 440
Top = 291
Width = 185
Height = 21
TabOrder = 5
Text = 'DemoTest.xml'
end
object
DBNavigator1: TDBNavigator
Left = 16
Top = 258
Width = 610
Height = 25
DataSource = DataSource1
TabOrder = 6
end
end
object ClientDataSet1: TClientDataSet
Aggregates = <>
Params = <>
ProviderName =
'XMLTransformProvider1'
Left = 432
Top = 360
end
object DataSource1: TDataSource
DataSet = ClientDataSet1
Left =
480
Top = 360
end
object XMLTransformProvider1:
TXMLTransformProvider
TransformRead.TransformationFile = 'ToDp.xtr'
TransformWrite.TransformationFile = 'ToDpIns.xtr'
XMLDataFile =
'userxml.xml'
Left = 368
Top = 360
end
end
