Question

我想使用以下格式在Delphi 10.1中创建XML文件

<EmployeeDB>
<Employees>
<Employee e.id="1">
  <eName>value from Edit Box edtName</eName>
<ePlace>value from Edit Box edtPlace</ePlace>
</Employee >
<Employee e.id="2">
  <eName>value from Edit Box edtName</eName>
<ePlace>value from Edit Box edtPlace</ePlace>
</Employee >
<Employee  e.id="3">
  <eName>value from Edit Box edtName</eName>
<ePlace>value from Edit Box edtPlace</ePlace>
</Employee >
</Employees>
</EmployeeDB>

我想从注册表单中获取数据，当单击“确定”按钮时，它应该将编辑框，RadioButtons等数据添加到XML文件中。

我是Delphi Programming的新手，帮我整理一下。

我尝试用这种方式编写代码：

unit XMLTrail;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics, XMLIntf, XMLDoc, ComObj, xmldom,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  Tfrm_XMLTrail = class(TForm)
    edt_eID: TEdit;
    edtName: TEdit;
    edtPlace: TEdit;
    Memo1: TMemo;
    btnAdd: TButton;
    procedure btn_AddClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    procedure LoadXML;
    procedure SaveXML;
  public
    { Public declarations }
    XMLDoc1: TXmlDocument;

    iNode, Root1, Root2, Child_Attrib_Name, Child_Attrib_Place: IXmlNode;
    function GetEmployeeDBNode(XMLDoc: TXmlDocument): IXmlNode;
    function GetEmployeesNode(EmployeeDBNode: IXmlNode): IXmlNode;

  end;

var
  frm_XMLTrail: Tfrm_XMLTrail;

implementation

{$R *.dfm}

const
  scXmlTemplate = '<EmployeeDB>'#13#10 + '  <Employees>'#13#10 +
    '  </Employees>'#13#10 + '</EmployeeDB>';

  scXmlFileName =
    'C:\Users\Rajesh\Documents\Embarcadero\Studio\Projects\Samples\XML trail\Win32\Debug\nicexml.xml';

procedure Tfrm_XMLTrail.btn_AddClick(Sender: TObject);
begin
  XMLDoc1.Active := true;
  iNode := XMLDoc1.DocumentElement;
  Root1 := iNode.ChildNodes.FindNode('Employees');
  Root2 := Root1.AddChild('Employee');
  Root2.Attributes['e.id'] := edt_eID.Text;
  Child_Attrib_Name := Root2.AddChild('eName');
  Child_Attrib_Name.Text := edtName.Text;
  Child_Attrib_Place := Root2.AddChild('ePlace');
  Child_Attrib_Place.Text := edtPlace.Text;
  XMLDoc1.Active := true;
  XMLDoc1.SaveToFile(scXmlFileName);

end;

procedure Tfrm_XMLTrail.FormCreate(Sender: TObject);
begin
  XMLDoc1 := TXmlDocument.Create(nil);
  if not FileExists(scXmlFileName) then
  begin
    // XMLDoc1 := TXmlDocument.Create(nil);
    XMLDoc1.Active := true;
    XMLDoc1.Options := [doNodeAutoIndent];
    iNode := XMLDoc1.AddChild('UmangEmployeeDB');
    Root1 := iNode.AddChild('Employees');
  end
  else
  begin
    LoadXML;
  end;
end;

procedure Tfrm_XMLTrail.LoadXML;
begin
  XMLDoc1.LoadFromFile(scXmlFileName);
  Memo1.Lines.Text := XMLDoc1.XML.Text;
  // SaveXML;
  // Memo1.Lines.LoadFromFile(scXmlFileName);

  // XMLDoc1 := TXmlDocument.Create(nil);
  // Assert(Root1 <> Nil);
end;

procedure Tfrm_XMLTrail.SaveXML;
begin
  Memo1.Lines.SaveToFile(scXmlFileName);
end;

end.

但是它返回了如下的XML文件：

<EmployeeDB>
    <Employees>
        <Employee e.id="2">
            <eName>sssss</eName>
            <ePlace>fgr</ePlace>
        </Employee>
        <Employee e.id="2">
            <eName>sssss</eName>
            <ePlace>fgr</ePlace>
        </Employee>
    </Employees>
</EmployeeDB>

应用程序的UI就像这个Image。

输入数据后单击“确定”按钮时，每次单击“确定”按钮时，都应通过创建新的<Employee/>节点将数据写入XML文件。

Answer 1

我通常不喜欢提交第二个答案但你似乎没有遵循我在第一篇文章中所说的话。

下面是一个示例项目，它生成一个新的Xml文件并添加一个新的Employee 每次单击btnAdd按钮时节点。希望代码中的注释足以让您前进。

请注意，此项目使用MSXML.Pas单元中定义的Xml接口，不使用XmlDoc单元。

unit XmlGenerateu;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, MSXML;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    edtName: TEdit;
    edtPlace: TEdit;
    btnAdd: TButton;
    procedure btnAddClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    procedure LoadXML;
    procedure SaveXML;
    procedure GenerateXML;
    function CreateEmployeeNode: IXmlDomElement;
  protected
  public
    XMLDoc : IXmlDomDocument;
    EmployeesNode : IXmlDomNode;
    NewEmployeeNode : IXmlDomNode;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

const
  scXmlTemplate =
    '<EmployeeDB>'#13#10
     + '  <Employees>'#13#10
     + '  </Employees>'#13#10
     + '</EmployeeDB>';

  scXmlFileName = 'C:\Temp\Employees.Xml';

procedure TForm1.btnAddClick(Sender: TObject);
begin
  NewEmployeeNode := CreateEmployeeNode;
  Memo1.Lines.Text := XmlDoc.xml;
  SaveXML;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  LoadXML;
end;

procedure TForm1.LoadXML;
begin
  //  If there is no existing Xml file create it from our Xml template
  //  and save it to disk
  if not FileExists(scXmlFileName) then begin
    Memo1.Lines.Text := scXmlTemplate;
    SaveXML;
  end;
  Memo1.Lines.LoadFromFile(scXmlFileName);

  //  Create the XmlDoc object
  XmlDoc := CoDomDocument.Create;
  //  Load it from Memo1
  Assert(XmlDoc.LoadXml(Memo1.Lines.Text));

  //  Find the Employees node
  EmployeesNode := XmlDoc.selectSingleNode('/EmployeeDB/Employees');
  //  Complain if we didn't find it
  Assert(EmployeesNode <> Nil);

end;

procedure TForm1.SaveXML;
begin
  Memo1.Lines.SaveToFile(scXmlFileName);
end;

function TForm1.CreateEmployeeNode : IXmlDomElement;
var
  EmployeeID : Integer;
  NameElement,
  PlaceElement : IXmlDomElement;
begin
  //  First, generate the ID for the new Employee
  EmployeeID :=  EmployeesNode.childNodes.length + 1;

  //  Next, get the XmlDoc to create a new Element
  Result := XmlDoc.createElement('Employee');

  //  Set the new Element's ID attribute
  Result.setAttribute('e.id', IntToStr(EmployeeID));

  //  Put the new Employee node at the end of the list of Employee nodes
  EmployeesNode.appendChild(Result);

  //  Finally, createt eName and ePlace children of the new Employee
  NameElement := XmlDoc.createElement('eName');
  NameElement.text := edtName.Text;
  Result.appendChild(NameElement);

  PlaceElement := XmlDoc.createElement('ePlace');
  PlaceElement.text := edtPlace.Text;
  Result.appendChild(PlaceElement);
end;

<强>更新

您在评论中询问是否可以使用TXmlDocument代替 MSXML.Pas单元中的接口。我认为这将是一个很好的自我指导练习所以我不打算用完整的代码来做，但这里有一些提示。

需要进行一些细节更改，例如如何从中加载XMLDocument Memo1，但主要的变化是如何找到Employees节点的XML文档。最简单的方法是使用XPath查询（请参阅上面的代码中的SelectSingleNode）但涉及使用相同的XML接口就像在MSXML.Pas中一样，如果你想这样做，你也可以避免使用 TXMLDocument的。如果你想避免使用XPath，那么你可以编写两个函数，返回EmployeeDB和Employees节点。这些可能看起来像这样

function TForm1.GetEmployeeDBNode(XmlDoc : TXmlDocument) : IXmlNode;
begin
  Result := XmlDoc.DocumentElement;
  Assert(Result <> Nil);
  Assert(Result.NodeName = 'EmployeeDB');
end;

function TForm1.GetEmployeesNode(EmployeeDBNode : IXmlNode) : IXmlNode;
begin
  Result := EmployeeDBNode.ChildNodes.First;
  Assert(Result <> Nil);
  Assert(Result.NodeName = 'Employees');
end;

您可以在CreateEmployeeNode的改编版本中使用这些功能通过在节点上调用AddChild（'Employee'）来添加新的Employee节点由GetEmployeesNode返回。

顺便说一下，编写这些假定XML文档具有固定结构的函数的需要说明了为什么使用XPath更为可取，因为它更容易适应不同的XML结构，例如，如果EmployeeDB嵌入在一些更大的Xml结构中。使用XPath，这只需要更改XPath查询字符串。

Answer 2

必须以这种方式修改代码，使用TXMLDocument创建XML文档，并在运行时将子元素附加到同一文档。谢谢你@MartynA先生的帮助..

unit XMLTrail;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics, XMLIntf, XMLDoc, ComObj, xmldom,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  Tfrm_XMLTrail = class(TForm)
    edt_eID: TEdit;
    edtName: TEdit;
    edtPlace: TEdit;
    Memo1: TMemo;
    btnAdd: TButton;
    procedure btn_AddClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    procedure LoadXML;
    procedure SaveXML;
  public
    { Public declarations }
    gXMLDoc1: TXmlDocument;
    giNode, gRoot1, gRoot2, gChild_Attrib_Name, gChild_Attrib_Place: IXmlNode;
    function GetEmployeeDBNode(XMLDoc: TXmlDocument): IXmlNode;
    function GetEmployeesNode(EmployeeDBNode: IXmlNode): IXmlNode;
    function GetEmployeeNodes(EmployeeNodes: IXmlNode): IXmlNode;
  end;

var
  frm_XMLTrail: Tfrm_XMLTrail;

implementation

{$R *.dfm}

const
  scXmlTemplate = '<EmployeeDB>'#13#10 + '  <Employees>'#13#10 +
    '  </Employees>'#13#10 + '</EmployeeDB>';

  scXmlFileName =
    '..\nicexml.xml';

procedure Tfrm_XMLTrail.btn_AddClick(Sender: TObject);
begin
  gXMLDoc1.Active := true;
  giNode := gXMLDoc1.DocumentElement;
  gRoot1 := giNode.ChildNodes.FindNode('Employees');
  gRoot2 := gRoot1.AddChild('Employee');
  gRoot2.Attributes['e.id'] := edt_eID.Text;
  gChild_Attrib_Name := gRoot2.AddChild('eName');
  gChild_Attrib_Name.Text := edtName.Text;
  gChild_Attrib_Place := gRoot2.AddChild('ePlace');
  gChild_Attrib_Place.Text := edtPlace.Text;
  gXMLDoc1.Active := true;
  gXMLDoc1.XML.Text := XMLDoc.FormatXMLData(gXMLDoc1.XML.Text);
  Memo1.Lines.Text := gXMLDoc1.XML.Text;
  SaveXML;
end;

procedure Tfrm_XMLTrail.FormCreate(Sender: TObject);
begin
  gXMLDoc1 := TXmlDocument.Create(self);
  if not FileExists(scXmlFileName) then
  begin
    // XMLDoc1 := TXmlDocument.Create(nil);
    gXMLDoc1.Active := true;
    gXMLDoc1.Options := [doNodeAutoIndent];
    giNode := gXMLDoc1.AddChild('EmployeeDB');
    gRoot1 := giNode.AddChild('Employees');
  end
  else
  begin
    LoadXML;
  end;
end;

procedure Tfrm_XMLTrail.LoadXML;
begin
  gXMLDoc1.LoadFromFile(scXmlFileName);
  gXMLDoc1.Active := true;
  Memo1.Lines.Text := gXMLDoc1.XML.Text;
end;

procedure Tfrm_XMLTrail.SaveXML;
begin
  Memo1.Lines.SaveToFile(scXmlFileName);
end;

function Tfrm_XMLTrail.GetEmployeeDBNode(XMLDoc: TXmlDocument): IXmlNode;
begin
  Result := XMLDoc.DocumentElement;
  Assert(Result <> Nil);
  Assert(Result.NodeName = 'EmployeeDB');
end;

function Tfrm_XMLTrail.GetEmployeesNode(EmployeeDBNode: IXmlNode): IXmlNode;
begin
  Result := EmployeeDBNode.ChildNodes.First;
  Assert(Result <> Nil);
  Assert(Result.NodeName = 'Employees');
end;

function Tfrm_XMLTrail.GetEmployeeNodes(EmployeeNodes: IXmlNode): IXmlNode;
begin
  Result := EmployeeNodes.ChildNodes.First;
  Assert(Result <> Nil);
  Assert(Result.NodeName = 'Employee');
end;

end.

在Delphi 10.1中生成XML文件并执行基本的XML操作？

2 个答案: