XmlDocument.CreateXmlDeclaration(String, String, String) Method

Definition

Namespace:

System.Xml

Assembly:

System.Xml.ReaderWriter.dll

Source:

XmlDocument.cs

Creates an XmlDeclaration node with the specified values.

public:
 virtual System::Xml::XmlDeclaration ^ CreateXmlDeclaration(System::String ^ version, System::String ^ encoding, System::String ^ standalone);

public virtual System.Xml.XmlDeclaration CreateXmlDeclaration (string version, string? encoding, string? standalone);

abstract member CreateXmlDeclaration : string * string * string -> System.Xml.XmlDeclaration
override this.CreateXmlDeclaration : string * string * string -> System.Xml.XmlDeclaration

Public Overridable Function CreateXmlDeclaration (version As String, encoding As String, standalone As String) As XmlDeclaration

Parameters

version

String

The version must be "1.0".

encoding

String

The value of the encoding attribute. This is the encoding that is used when you save the XmlDocument to a file or a stream; therefore, it must be set to a string supported by the Encoding class, otherwise Save(String) fails. If this is null or String.Empty, the Save method does not write an encoding attribute on the XML declaration and therefore the default encoding, UTF-8, is used.

Note: If the XmlDocument is saved to either a TextWriter or an XmlTextWriter, this encoding value is discarded. Instead, the encoding of the TextWriter or the XmlTextWriter is used. This ensures that the XML written out can be read back using the correct encoding.

standalone

String

The value must be either "yes" or "no". If this is null or String.Empty, the Save method does not write a standalone attribute on the XML declaration.

Returns

XmlDeclaration

The new XmlDeclaration node.

Exceptions

ArgumentException

The values of version or standalone are something other than the ones specified above.

Examples

The following example creates an XML declaration and adds it to the document.

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   XmlDocument^ doc = gcnew XmlDocument;
   doc->LoadXml( "<book genre='novel' ISBN='1-861001-57-5'><title>Pride And Prejudice</title></book>" );
   
   //Create an XML declaration. 
   XmlDeclaration^ xmldecl;
   xmldecl = doc->CreateXmlDeclaration( "1.0", nullptr, nullptr );
   
   //Add the new node to the document.
   XmlElement^ root = doc->DocumentElement;
   doc->InsertBefore( xmldecl, root );
   Console::WriteLine( "Display the modified XML..." );
   doc->Save( Console::Out );
}

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

public class Sample
{
  public static void Main()
  {
    XmlDocument doc = new XmlDocument();
    doc.LoadXml("<book genre='novel' ISBN='1-861001-57-5'>" +
                "<title>Pride And Prejudice</title>" +
                "</book>");

    //Create an XML declaration.
    XmlDeclaration xmldecl;
    xmldecl = doc.CreateXmlDeclaration("1.0",null,null);

    //Add the new node to the document.
    XmlElement root = doc.DocumentElement;
    doc.InsertBefore(xmldecl, root);

    Console.WriteLine("Display the modified XML...");
    doc.Save(Console.Out);
  }
}

Option Explicit
Option Strict

Imports System.IO
Imports System.Xml

Public Class Sample
    
    Public Shared Sub Main()
        Dim doc As New XmlDocument()
        doc.LoadXml("<book genre='novel' ISBN='1-861001-57-5'>" & _
                    "<title>Pride And Prejudice</title>" & _
                    "</book>")
        
        'Create an XML declaration. 
        Dim xmldecl As XmlDeclaration
        xmldecl = doc.CreateXmlDeclaration("1.0", Nothing, Nothing)
        
        'Add the new node to the document.
        Dim root As XmlElement = doc.DocumentElement
        doc.InsertBefore(xmldecl, root)
        
        Console.WriteLine("Display the modified XML...")
        doc.Save(Console.Out)
    End Sub
End Class

Remarks

The attributes are exposed as special properties on the XmlDeclaration node, and not as XmlAttribute nodes.

Although this method creates the new object in the context of the document, it does not automatically add the new object to the document tree. To add the new object, you must explicitly call one of the node insert methods.

According to the W3C Extensible Markup Language (XML) 1.0 recommendation, the XmlDeclaration node must be the first node in the document.

This method is a Microsoft extension to the Document Object Model (DOM).

See also

• XmlDeclaration