It is important to mention that a node always belongs to a particular document, even if it was just created or has been removed from the tree. The document to which the node belongs is returned by the Node.Document property.

A node always belongs to a document, because some vital document-wide structures such as styles and lists are stored in the Document node. For example, it is not possible to have a Paragraph without a Document because each paragraph has a style assigned to it and the style is defined globally for the document.

Example CreatingNodeRequiresDocument

Shows that when you create any node, it requires a document that will own the node.

[C#]

 

// Open a file from disk.

Document doc = new Document();

 

// Creating a new node of any type requires a document passed into the constructor.

Paragraph para = new Paragraph(doc);

 

// The new paragraph node does not yet have a parent.

Assert.IsNull(para.ParentNode);

 

// But the paragraph node knows its document.

Assert.AreEqual(doc, para.Document);

 

// The fact that a node always belongs to a document allows us to access and modify

// properties that reference the document-wide data such as styles or lists.

para.ParagraphFormat.StyleName = "Heading 1";

 

// Now add the paragaph to the main text of the first section.

doc.FirstSection.Body.AppendChild(para);

 

// The paragraph node is now a child of the Body node.

Assert.IsNotNull(para.ParentNode);

 

 

[Visual Basic]

 

' Open a file from disk.

Dim doc As Document = New Document()

 

' Creating a new node of any type requires a document passed into the constructor.

Dim para As Paragraph = New Paragraph(doc)

 

' The new paragraph node does not yet have a parent.

Assert.IsNull(para.ParentNode)

 

' But the paragraph node knows its document.

Assert.AreEqual(doc, para.Document)

 

' The fact that a node always belongs to a document allows us to access and modify

' properties that reference the document-wide data such as styles or lists.

para.ParagraphFormat.StyleName = "Heading 1"

 

' Now add the paragaph to the main text of the first section.

doc.FirstSection.Body.AppendChild(para)

 

' The paragraph node is now a child of the Body node.

Assert.IsNotNull(para.ParentNode)

 

 

[Java]

 

// Open a file from disk.

Document doc = new Document();

 

// Creating a new node of any type requires a document passed into the constructor.

Paragraph para = new Paragraph(doc);

 

// The new paragraph node does not yet have a parent.

Assert.assertNull(para.getParentNode());

 

// But the paragraph node knows its document.

Assert.assertEquals(doc, para.getDocument());

 

// The fact that a node always belongs to a document allows us to access and modify

// properties that reference the document-wide data such as styles or lists.

para.getParagraphFormat().setStyleName("Heading 1");

 

// Now add the paragaph to the main text of the first section.

doc.getFirstSection().getBody().appendChild(para);

 

// The paragraph node is now a child of the Body node.

Assert.assertNotNull(para.getParentNode());