XmlTextReader.Value 属性

项目
08/17/2007

获取当前节点的文本值。

**命名空间:**System.Xml
**程序集:**System.Xml（在 system.xml.dll 中）

语法

声明
Public Overrides ReadOnly Property Value As String
用法
Dim instance As XmlTextReader
Dim value As String

value = instance.Value

public override string Value { get; }

public:
virtual property String^ Value {
    String^ get () override;
}

/** @property */
public String get_Value ()

public override function get Value () : String

属性值

返回的值取决于节点的 NodeType。下表列出具有要返回的值的节点类型。所有其他节点类型返回 String.Empty。

节点类型	值
Attribute	属性值。
CDATA	CDATA 节的内容。
Comment	注释的内容。
DocumentType	内部子集。
ProcessingInstruction	全部内容（不包括指令目标）。
SignificantWhitespace	xml:space= 'preserve' 范围中的空白。
Text	文本节点的内容。
Whitespace	标记之间的空白。
XmlDeclaration	声明的内容。

备注

提示

在 Microsoft .NET Framework 2.0 版版本中，推荐的做法是使用 System.Xml.XmlReader.Create 方法创建 XmlReader 实例。这使您可以充分利用此版本中引入的新功能。有关更多信息，请参见创建 XML 读取器。

示例

下面的示例读取 XML 文件并显示每个节点。

Option Strict
Option Explicit

Imports System
Imports System.IO
Imports System.Xml

'Reads an XML document
Public Class Sample
    Private Const filename As String = "items.xml"
    
    Public Shared Sub Main()
        Dim reader As XmlTextReader = Nothing
        
        Try
            ' Load the reader with the data file and ignore all white space nodes.         
            reader = New XmlTextReader(filename)
            reader.WhitespaceHandling = WhitespaceHandling.None
            
            ' Parse the file and display each of the nodes.
            While reader.Read()
                Select Case reader.NodeType
                    Case XmlNodeType.Element
                        Console.Write("<{0}>", reader.Name)
                    Case XmlNodeType.Text
                        Console.Write(reader.Value)
                    Case XmlNodeType.CDATA
                        Console.Write("<![CDATA[{0}]]>", reader.Value)
                    Case XmlNodeType.ProcessingInstruction
                        Console.Write("<?{0} {1}?>", reader.Name, reader.Value)
                    Case XmlNodeType.Comment
                        Console.Write("<!--{0}-->", reader.Value)
                    Case XmlNodeType.XmlDeclaration
                        Console.Write("<?xml version='1.0'?>")
                    Case XmlNodeType.Document
                    Case XmlNodeType.DocumentType
                        Console.Write("<!DOCTYPE {0} [{1}]", reader.Name, reader.Value)
                    Case XmlNodeType.EntityReference
                        Console.Write(reader.Name)
                    Case XmlNodeType.EndElement
                        Console.Write("</{0}>", reader.Name)
                End Select
            End While
        
        Finally
            If Not (reader Is Nothing) Then
                reader.Close()
            End If
        End Try
    End Sub 'Main 
End Class 'Sample

using System;
using System.IO;
using System.Xml;

public class Sample {

  private const String filename = "items.xml";

  public static void Main() {
  
     XmlTextReader reader = null;

     try {
       
        // Load the reader with the data file and ignore all white space nodes.         
        reader = new XmlTextReader(filename);
        reader.WhitespaceHandling = WhitespaceHandling.None;

        // Parse the file and display each of the nodes.
        while (reader.Read()) {
           switch (reader.NodeType) {
             case XmlNodeType.Element:
               Console.Write("<{0}>", reader.Name);
               break;
             case XmlNodeType.Text:
               Console.Write(reader.Value);
               break;
             case XmlNodeType.CDATA:
               Console.Write("<![CDATA[{0}]]>", reader.Value);
               break;
             case XmlNodeType.ProcessingInstruction:
               Console.Write("<?{0} {1}?>", reader.Name, reader.Value);
               break;
             case XmlNodeType.Comment:
               Console.Write("<!--{0}-->", reader.Value);
               break;
             case XmlNodeType.XmlDeclaration:
               Console.Write("<?xml version='1.0'?>");
               break;
             case XmlNodeType.Document:
               break;
             case XmlNodeType.DocumentType:
               Console.Write("<!DOCTYPE {0} [{1}]", reader.Name, reader.Value);
               break;
             case XmlNodeType.EntityReference:
               Console.Write(reader.Name);
               break;
             case XmlNodeType.EndElement:
               Console.Write("</{0}>", reader.Name);
               break;
           }       
        }           
     }

     finally {
        if (reader!=null)
          reader.Close();
     }
  }
} // End class

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   XmlTextReader^ reader = nullptr;
   String^ filename = "items.xml";
   try
   {
      
      // Load the reader with the data file and ignore all white space nodes.         
      reader = gcnew XmlTextReader( filename );
      reader->WhitespaceHandling = WhitespaceHandling::None;
      
      // Parse the file and display each of the nodes.
      while ( reader->Read() )
      {
         switch ( reader->NodeType )
         {
            case XmlNodeType::Element:
               Console::Write( "<{0}>", reader->Name );
               break;

            case XmlNodeType::Text:
               Console::Write( reader->Value );
               break;

            case XmlNodeType::CDATA:
               Console::Write( "<![CDATA[{0}]]>", reader->Value );
               break;

            case XmlNodeType::ProcessingInstruction:
               Console::Write( "<?{0} {1}?>", reader->Name, reader->Value );
               break;

            case XmlNodeType::Comment:
               Console::Write( "<!--{0}-->", reader->Value );
               break;

            case XmlNodeType::XmlDeclaration:
               Console::Write( "<?xml version='1.0'?>" );
               break;

            case XmlNodeType::Document:
               break;

            case XmlNodeType::DocumentType:
               Console::Write( "<!DOCTYPE {0} [{1}]", reader->Name, reader->Value );
               break;

            case XmlNodeType::EntityReference:
               Console::Write( reader->Name );
               break;

            case XmlNodeType::EndElement:
               Console::Write( "</{0}>", reader->Name );
               break;
         }
      }
   }
   finally
   {
      if ( reader != nullptr )
            reader->Close();
   }

}

import System.*;
import System.IO.*;
import System.Xml.*;

public class Sample
{
    private static String fileName = "items.xml";

    public static void main(String[] args)
    {
        XmlTextReader reader = null;
        try {

            // Load the reader with the data file and ignore 
            //all white space nodes.         
            reader = new XmlTextReader(fileName);
            reader.set_WhitespaceHandling(WhitespaceHandling.None);

            // Parse the file and display each of the nodes.
            while(reader.Read()) {
                switch(reader.get_NodeType() ) {
                    case XmlNodeType.Element : 
                        Console.Write("<{0}>", reader.get_Name());
                        break;
                    case XmlNodeType.Text : 
                        Console.Write(reader.get_Value());
                        break;
                    case XmlNodeType.CDATA : 
                        Console.Write("<![CDATA[{0}]]>", reader.get_Value());
                        break;
                    case XmlNodeType.ProcessingInstruction : 
                        Console.Write("<?{0} {1}?>", reader.get_Name(),
                        reader.get_Value());
                        break;
                    case XmlNodeType.Comment : 
                        Console.Write("<!--{0}-->", reader.get_Value());
                        break;
                    case XmlNodeType.XmlDeclaration : 
                        Console.Write("<?xml version='1.0'?>");
                        break;
                    case XmlNodeType.Document : 
                        break;
                    case XmlNodeType.DocumentType : 
                        Console.Write("<!DOCTYPE {0} [{1}]", reader.get_Name(),
                        reader.get_Value());
                        break;
                    case XmlNodeType.EntityReference : 
                        Console.Write(reader.get_Name());
                        break;
                    case XmlNodeType.EndElement : 
                        Console.Write("</{0}>", reader.get_Name());
                        break;
                }
            }
        }
        finally {
            if (reader != null) {
                reader.Close();
            }
        }
    } //main
} // End class Sample

该示例使用文件 items.xml。

<?xml version="1.0"?>
<!-- This is a sample XML document -->
<!DOCTYPE Items [<!ENTITY number "123">]>
<Items>
  <Item>Test with an entity: &number;</Item>
  <Item>test with a child element <more/> stuff</Item>
  <Item>test with a CDATA section <![CDATA[<456>]]> def</Item>
  <Item>Test with an char entity: &#65;</Item>
  <!-- Fourteen chars in this element.-->
  <Item>1234567890ABCD</Item>
</Items>

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

通过

XmlTextReader.Value 属性

语法

属性值

备注

示例

平台

版本信息

.NET Framework

.NET Compact Framework

请参见

参考

其他资源

其他资源