XPathNavigator.CreateAttribute(String, String, String, String) Method

Definition

Namespace:

System.Xml.XPath

Assembly:

System.Xml.ReaderWriter.dll

Source:

XPathNavigator.cs

Creates an attribute node on the current element node using the namespace prefix, local name and namespace URI specified with the value specified.

public:
 virtual void CreateAttribute(System::String ^ prefix, System::String ^ localName, System::String ^ namespaceURI, System::String ^ value);

public virtual void CreateAttribute (string? prefix, string localName, string? namespaceURI, string? value);

abstract member CreateAttribute : string * string * string * string -> unit
override this.CreateAttribute : string * string * string * string -> unit

Public Overridable Sub CreateAttribute (prefix As String, localName As String, namespaceURI As String, value As String)

Parameters

prefix

String

The namespace prefix of the new attribute node (if any).

localName

String

The local name of the new attribute node which cannot Empty or null.

namespaceURI

String

The namespace URI for the new attribute node (if any).

value

String

The value of the new attribute node. If Empty or null are passed, an empty attribute node is created.

Exceptions

InvalidOperationException

The XPathNavigator is not positioned on an element node.

NotSupportedException

The XPathNavigator does not support editing.

Examples

In the following example, a new discount attribute is created on the price child element of the first book element in the contosoBooks.xml file.

XmlDocument^ document = gcnew XmlDocument();
document->Load("contosoBooks.xml");
XPathNavigator^ navigator = document->CreateNavigator();

navigator->MoveToChild("bookstore", "http://www.contoso.com/books");
navigator->MoveToChild("book", "http://www.contoso.com/books");
navigator->MoveToChild("price", "http://www.contoso.com/books");

navigator->CreateAttribute("", "discount", "", "1.00");

navigator->MoveToParent();
Console::WriteLine(navigator->OuterXml);

XmlDocument document = new XmlDocument();
document.Load("contosoBooks.xml");
XPathNavigator navigator = document.CreateNavigator();

navigator.MoveToChild("bookstore", "http://www.contoso.com/books");
navigator.MoveToChild("book", "http://www.contoso.com/books");
navigator.MoveToChild("price", "http://www.contoso.com/books");

navigator.CreateAttribute("", "discount", "", "1.00");

navigator.MoveToParent();
Console.WriteLine(navigator.OuterXml);

Dim document As XmlDocument = New XmlDocument()
document.Load("contosoBooks.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

navigator.MoveToChild("bookstore", "http://www.contoso.com/books")
navigator.MoveToChild("book", "http://www.contoso.com/books")
navigator.MoveToChild("price", "http://www.contoso.com/books")

navigator.CreateAttribute("", "discount", "", "1.00")

navigator.MoveToParent()
Console.WriteLine(navigator.OuterXml)

The example takes the contosoBooks.xml file as an input.

<?xml version="1.0" encoding="utf-8" ?>  
<bookstore xmlns="http://www.contoso.com/books">  
    <book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">  
        <title>The Autobiography of Benjamin Franklin</title>  
        <author>  
            <first-name>Benjamin</first-name>  
            <last-name>Franklin</last-name>  
        </author>  
        <price>8.99</price>  
    </book>  
    <book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">  
        <title>The Confidence Man</title>  
        <author>  
            <first-name>Herman</first-name>  
            <last-name>Melville</last-name>  
        </author>  
        <price>11.99</price>  
    </book>  
    <book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">  
        <title>The Gorgias</title>  
        <author>  
            <name>Plato</name>  
        </author>  
        <price>9.99</price>  
    </book>  
</bookstore>  

Remarks

Namespace prefix and URI values can be obtained using the LookupPrefix or LookupNamespace method. For example, the following syntax creates an attribute by using the in-scope namespace xmlns:bk="http://www.contoso.com/books":

editor.CreateAttribute(navigator.Prefix, "attributeName", LookupNamespace(navigator.Prefix), "text")  

This creates the new attribute <bk:element attributeName="text"/> on the current element.

The following are important notes to consider when using the CreateAttribute method.

• If the namespace prefix specified is String.Empty or null, the prefix for the namespace URI of the new attribute is obtained from the current namespaces in-scope. If there is no namespace prefix assigned to the specified namespace URI at the current scope, a namespace prefix is automatically generated. For example to create a new attribute on an element in the default namespace of the contosoBooks.xml file, (xmlns="http://www.contoso.com/books"), you specify null or String.Empty for both the namespace prefix and namespace URI parameters. Specifying http://www.contoso.com/books as the namespace URI parameter will cause the CreateAttribute method to auto generate a namespace prefix for the new attribute.

• If the new attribute created is a namespace node which conflicts with a namespace declaration on the element, either because the namespace prefix chosen is used by another namespace declaration at the same scope, or because the prefix chosen is the same as that of the element but is bound to a different namespace URI, an exception is thrown.

• The CreateAttribute method does not affect the position of the XPathNavigator.