Delphi6

delphi6的新特性 
BizSnap™ simplifies eBusiness integration by easily and seamlessly creating and using XML/SOAP based Web Services
Delphi 6 radically simplifies building next-generation eBusiness applications on the Internet with complete SOAP based Web Services and XML data exchange support. The seamless integration of XML and Web Services technologies with Delphi 6 delivers the only Rapid Application Development for industry standard Web Services and B2B, B2C, and P2P integration over the Internet.

WebSnap™ is a component-based Web application development framework that supports leading Web Application Servers, including Apache, Netscape and Microsoft Internet Information Services (IIS)
WebSnap integrates the power of Delphi directly into today's Web site development teams. With WebSnap, Delphi applications can seamless integrate with Web sites and Web site development teams using today's popular HTML development environments such as Dreamweaver, Frontpage, VBScript, and JavaScript.

DataSnap™ delivers high-performance, Web Service-enabled database middleware that enables any client application or service to easily connect with any major database over the Internet
DataSnap supports all major database servers such as Oracle, MS-SQL Server, Informix, IBM DB2, Sybase and InterBase. Client applications connect to high-performance DataSnap servers through industry standard SOAP/XML HTTP connections over the Internet without bulky database client drivers and complex configuration requirements. DCOM, CORBA, and TCP/IP connections are also supported.

Build Single Source Windows/Linux Applications
Delphi 6 is Kylix compatible! Use the Cross-platform CLX™ component library and visual designers to build high-performance portable applications for Windows that can be easily re-compiled on Linux with Borland Kylix (sold separately). Plus! Bring CLX based Linux applications from Kylix into Delphi 6 to easily re-compile on Windows. Delphi 6 includes BaseCLX, VisualCLX, DataCLX, and NetCLX components.

Delphi 6 Borland AppServer Integration
Connect any Delphi 6 application or Web Service with Borland AppServer/EJBs using new SIDL (Simple IDL). Easily build ultra high-performance rich GUI Windows clients for EJB based AppServer applications. Publish AppServer EJB functionality to the world over Internet as industry standard SOAP/XML Web Services.

Borland VisiBroker for Delphi - Client and Server Development
Build ultra-high performance rich GUI Windows and Web Browser clients for Visibroker CORBA and AppServer/EJB applications. And now in Delphi 6 build CORBA Visibroker server objects that are interoperable with any CORBA client or object in a heterogeneous IT environment.

Latest Windows 2000/ME and Office 2000 GUI Support
Build the most modern user interfaces with new ActionBands, ActionManagers, and Shell Controls to easily create dynamic user interfaces that follow the latest Microsoft UI trends. Take all the work out of complex user interfaces while letting end-users fully customize their own UI experience.

Delphi 6 含有许多更新更强的XML支持功能，增加了XML文件编程，XML数据绑定向导，XML映象和BizSnap(SOAP/XML Web服务)。我在上一篇文章论述了Delphi 6中的XML文件编程(XML Document Programming)。本文是三篇论述Delphi 6中XML功能系列文章的第二篇，论述Delphi 6中的XML数据绑定(XML Data Binding)。

XML文件编程
XMLDocument组件让我们能够遍历和编辑XML文件。但是在上一篇文章中我提到了，我们只能与无类型节点打交道，必须记住节点元素的名字。这意味着无法进行实时编译调试！幸亏的是，如果Delphi只能处理这样简单的问题就不成其为Delphi了。运用XML的内容相关结构可以做更高级的应用，这就是Delphi 6的XML数据绑定向导(XML Data Binding Wizard)。

XML数据绑定
在Delphi 6的模块仓库(Object Repository)中可以找到XML数据绑定向导(XML Data Binding Wizard)。程序员能够用它生成相应的接口和类来访问与修改XML文件数据，诸如ClientDataSetXML数据，ADO XML数据，其它XML文件数据(如我们在前文用到的Clinic.xml，本文继续使用这个简单的XML文件作示例)。

现在开始吧，启动Delphi 6，在主菜单上选择File | New - Other，然后在仓库中选择XML Data Binding，如图1所示。

向导有三个页面。第一页定义XML纲(Schema)或XML文件(本例用Clinic.xml)，如图2所示。
在资源输入框内输入XML纲(Schema)或XML文件。“选项”(Options)对话框定义编码选项和数据类型映射关系(Data Type map)。以后我们还会谈到这些选项。

向导的第二页显示了树结构和节点数据类型(亦即向导生成了些什么样的代码)。图3可以看到我的XML文件结构。
可以看到XML文件里描述的嵌套节点(ClinicsType与ClinicType)和单节点(String)。这时可以打开选项(Options)对话框(图4)，修改编码(比如修改前缀)和数据类型映射。

向导的第三页显示生成的相应接口和类。可以把这些结果保存到文件(例如生成Clinic.xdb)。
结果(存储为Clinic.xdb文件)显示如下。我们得到一个ClinicsType类型的Clinics元素，其中包括ClinicType类型的Clinic系列元素。

文件同时定义ClinicType类型的Clinic元素包含一系列字符串元素(Title, Date和Topics)。

生成代码
向导生成的代码可以直接在应用中使用。不幸的是，Delphi 6有时会产生“非法操作”的出错信息。重新执行一遍，它又能工作了。
以下是生成的代码(Clinic.pas)：

  {****************************************************}
  {                                                    }
  {              Delphi XML Data Binding               }
  {                                                    }
  {         Generated on: 2001/11/07 00:37:00          }
  {       Generated from: D:\D6Clinic\src\Clinic.xml   }
  {   Settings stored in: D:\D6Clinic\src\Clinic.xdb   }
  {                                                    }
  {****************************************************}
  unit Clinic;
  interface
  uses xmldom, XMLDoc, XMLIntf;

  type

  { Forward Decls }

    IXMLClinicsType = interface;
    IXMLClinicType = interface;

  { IXMLClinicsType }

  IXMLClinicsType = interface(IXMLNodeCollection)
    ['{06723E03-662D-11D5-81CE-00104BF89DAD}']
    { Property Accessors }
    function Get_Clinic(Index: Integer): IXMLClinicType;
    { Methods & Properties }
    function Add: IXMLClinicType;
    function Insert(const Index: Integer): IXMLClinicType;
    property Clinic[Index: Integer]: IXMLClinicType
      read Get_Clinic; default;
  end;

  { IXMLClinicType }

  IXMLClinicType = interface(IXMLNode)
    ['{06723E04-662D-11D5-81CE-00104BF89DAD}']
    { Property Accessors }
    function Get_No: WideString;
    function Get_Title: WideString;
    function Get_Date: WideString;
    function Get_Topics: WideString;
    procedure Set_No(Value: WideString);
    procedure Set_Title(Value: WideString);
    procedure Set_Date(Value: WideString);
    procedure Set_Topics(Value: WideString);
    { Methods & Properties }
    property No: WideString read Get_No write Set_No;
    property Title: WideString read Get_Title write Set_Title;
    property Date: WideString read Get_Date write Set_Date;
    property Topics: WideString read Get_Topics write Set_Topics;
  end;

  { Forward Decls }

    TXMLClinicsType = class;
    TXMLClinicType = class;

  { TXMLClinicsType }

  TXMLClinicsType = class(TXMLNodeCollection, IXMLClinicsType)
  protected
    { IXMLClinicsType }
    function Get_Clinic(Index: Integer): IXMLClinicType;
    function Add: IXMLClinicType;
    function Insert(const Index: Integer): IXMLClinicType;
  public
    procedure AfterConstruction; override;
  end;

  { TXMLClinicType }

  TXMLClinicType = class(TXMLNode, IXMLClinicType)
  protected
    { IXMLClinicType }
    function Get_No: WideString;
    function Get_Title: WideString;
    function Get_Date: WideString;
    function Get_Topics: WideString;
    procedure Set_No(Value: WideString);
    procedure Set_Title(Value: WideString);
    procedure Set_Date(Value: WideString);
    procedure Set_Topics(Value: WideString);
  end;

  { Global Functions }

  function GetClinics(Doc: IXMLDocument): IXMLClinicsType;
  function LoadClinics(const FileName: WideString): IXMLClinicsType;
  function NewClinics: IXMLClinicsType;

这里有二个接口类型：IXMLClinicsType和IXMLClinicType；用二个类(TXMLClinicsType和TXMLClinicType)来执行这二个接口。另外还有三个全局函数：GetClinics (获得根元素)，LoadClinics (从外部XML文件加载)和NewClinics (在内存生成新文件)。

用法
使用生成的Clinic.pas单元是很容易的。跟前一篇文章的做法一样，使用XMLDocument组件(在Inernet标签内)。不过我们不再使用无类型节点了，我们可以调用GetClinics函数获得IXMLClinicsType类型。以下是具体操作过程：

在Delphi 6建立一个新的应用(project)
在XML数据绑定向导指引下建立Clinic.pas文件(经过命名存盘 - 译者)
在主窗体上加入一个XMLDocument组件，其FileName属性为Clinic.xml
在主窗体的OnCreate事件中加入以下代码：
  procedure TForm1.FormCreate(Sender: TObject);
  var
    Clinics: IXMLClinicsType;
  begin
    Clinics := GetClinics(XMLDocument1);
  end;

把Clinics变量放到主窗体中是很有用的，这样就可以在主窗体运行期间使用Clinics接口。使用IXMLClinicsType变量类型要比以前使用普通XMLDocument组件方便多了。现在可以通过Get_Clinic方法来获得各个Clinic元素，还可以在特定位置插入新的Clinic元素。用Clinics.Clinic可以获得节点元素，用Getter和Setter方法可以得到或设置元素值。现在可以直接访问No, Title, Date, Topics等属性了：
  procedure TForm1.ButtonGetClick(Sender: TObject);
  var
    Clinic: IXMLClinicType;
  begin
    Clinic := Clinics.Clinic[0];
    EditNo.Text := Clinic.No;
    EditTitle.Text := Clinic.Title;
    EditDate.Text := Clinic.Date;
    EditTopics.Text := Clinic.Topics
  end;

可以在Clinic.pas中看到，Getter和Setter是方法而不是属性(实际上，我始终认为使用属性更清楚些)。但是Delphi 6让你看到的却是属性描述而不是方法本身(Delphi 6的另一个受欢迎的优点)。将上面这段代码与前一篇文章使用的方法相比较，就能感到操作方便多了。

下面的例子在XML树的末尾加入一个节点：
  procedure TForm1.ButtonAddClick(Sender: TObject);
  begin
    with Clinics.Add do
    begin
      No := '2001-2-8;  // 8th Clinic of the 2nd series of 2001
      Title := 'Special Kylix 2 Clinic';
      Date := '2001/12/21';
      Topics := 'Kylix 2 New Features'
    end
  end;

如果没有把XMLDocument组件的AutoSave设置为真，可以用以下方法保存更动结果：
  procedure TForm1.FormDestroy(Sender: TObject);
  begin
    XMLDocument1.SaveToFile;
  end;

这就是XML数据绑定向导，一个非常方便的方法。它能做得越来越好。

讨论区