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XmlDocument.GetElementById(String) 方法

定義

取得具有指定 ID 的 XmlElement

public:
 virtual System::Xml::XmlElement ^ GetElementById(System::String ^ elementId);
public virtual System.Xml.XmlElement? GetElementById (string elementId);
public virtual System.Xml.XmlElement GetElementById (string elementId);
abstract member GetElementById : string -> System.Xml.XmlElement
override this.GetElementById : string -> System.Xml.XmlElement
Public Overridable Function GetElementById (elementId As String) As XmlElement

參數

elementId
String

要比對的屬性 ID。

傳回

XmlElement

具有相符 ID 的 XmlElement;如果找不到相符的項目,則為 null

範例

下列範例使用 GetElementById 方法。

#using <System.Xml.dll>

using namespace System;
using namespace System::Xml;
int main()
{
   XmlDocument^ doc = gcnew XmlDocument;
   doc->Load( "ids.xml" );
   
   //Get the first element with an attribute of type ID and value of A111.
   //This displays the node <Person SSN="A111" Name="Fred"/>.
   XmlElement^ elem = doc->GetElementById( "A111" );
   Console::WriteLine( elem->OuterXml );
   
   //Get the first element with an attribute of type ID and value of A222.
   //This displays the node <Person SSN="A222" Name="Tom"/>.
   elem = doc->GetElementById( "A222" );
   Console::WriteLine( elem->OuterXml );
}


using System;
using System.Xml;

public class Sample
{
  public static void Main()
  {
    XmlDocument doc = new XmlDocument();
    doc.Load("ids.xml");

    //Get the first element with an attribute of type ID and value of A111.
    //This displays the node <Person SSN="A111" Name="Fred"/>.
    XmlElement elem = doc.GetElementById("A111");
    Console.WriteLine( elem.OuterXml );

    //Get the first element with an attribute of type ID and value of A222.
    //This displays the node <Person SSN="A222" Name="Tom"/>.
    elem = doc.GetElementById("A222");
    Console.WriteLine( elem.OuterXml );
  }
}
Option Explicit
Option Strict

Imports System.Xml

Public Class Sample
    
    Public Shared Sub Main()
        Dim doc As New XmlDocument()
        doc.Load("ids.xml")
        
        'Get the first element with an attribute of type ID and value of A111.
        'This displays the node <Person SSN="A111" Name="Fred"/>.
        Dim elem As XmlElement = doc.GetElementById("A111")
        Console.WriteLine(elem.OuterXml)
        
        'Get the first element with an attribute of type ID and value of A222.
        'This displays the node <Person SSN="A222" Name="Tom"/>.
        elem = doc.GetElementById("A222")
        Console.WriteLine(elem.OuterXml)
    End Sub
End Class

此範例會使用 檔案 ids.xml ,作為輸入。

<!DOCTYPE root [  
  <!ELEMENT root ANY>   
  <!ELEMENT Person ANY>   
  <!ELEMENT Customer EMPTY>  
  <!ELEMENT Team EMPTY>  
  <!ATTLIST Person SSN ID #REQUIRED>  
  <!ATTLIST Customer id IDREF #REQUIRED >  
  <!ATTLIST Team members IDREFS #REQUIRED>]>  
<root>  
  <Person SSN='A111' Name='Fred'/>  
  <Person SSN='A222' Name='Tom'/>  
  <Customer id='A222334444'/>  
  <Team members='A222334444 A333445555'/>  
</root>  

備註

如果檔有多個具有相符識別碼的專案,這個方法會傳回檔中的第一個相符專案。

注意

DOM 實作必須有定義哪些屬性屬於識別碼類型的資訊。 雖然類型識別碼的屬性可以在 XSD 架構或 DTD 中定義,但此版本的產品僅支援在 DTD 中定義的屬性。 除非在 DTD 中定義,否則名稱為 「ID」 的屬性不是類型識別碼。 實作,其中未知的屬性是否必須是型別識別碼傳回 null

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