Additional IXMLDOMDocumentType Properties
| Name | Description |
|---|---|
| entities | Returns a node list containing references to the entity objects declared in the DTD |
| name | Returns the name of the document type for the document |
| notations | Returns a node list containing references to the notation objects in the DTD |
Now that the IXMLDOMDocumentType interface contains information associated with the DTD, let's create a DTD named Books.dtd for the document using the following text:
<!ELEMENT northwind:BOOKS (item)>
<!ATTLIST northwind:BOOKS xmlns:northwind CDATA #FIXED
"www.northwindtraders.com/PO">
<!ENTITY % ItemElements "(title, author, price, quantity)">
<!ENTITY copyright "©">
<!ELEMENT item %ItemElements;>
<!ELEMENT title (#PCDATA)>
<!ATTLIST title language CDATA #REQUIRED>
<!ELEMENT author (#PCDATA)>
<!ELEMENT price (#PCDATA)>
<!ELEMENT quantity (#PCDATA)>
Notice that we declared a general entity called copyright in the above DTD, thus we need to reference this entity in the Books.xml document. We also need to add a line of code to the XML document so that it will reference the DTD:
<?xml version="1.0" ?>
<!DOCTYPE northwind:BOOKS SYSTEM "c:\Books.dtd">
<northwind:BOOKS xmlns:northwind="www.northwindtraders.com/PO">
<item>
<title language="English">Number, the Language of Science
©right;
</title>
<author>Danzig</author>
<price>5.95</price>
<quantity>3</quantity>
</item>
</northwind:BOOKS>
NOTE
Remember that the DTD has no ability to resolve namespaces. Thus, you must declare the elements that use the namespace with the namespace prefix and define an attribute for the namespace. The XML document, though, can resolve the namespace information.
Now let's take a look at how to use the properties of the IXMLDOMDocumentType interface in our example application. First, add another command button to the frmDOMTest form with the name cmdDocumentType and the caption Document Type. Then add the following code to the click event of this button:
Private Sub cmdDocumentType_Click()
Dim objDocumentType As IXMLDOMDocumentType
Dim objXMLDoc As DOMDocument
Set objXMLDoc = New DOMDocument
objXMLDoc.async = False
objXMLDoc.Load ("c:\Books.xml")
Set objDocumentType = objXMLDoc.doctype
Debug.Print objDocumentType.Name
Debug.Print objDocumentType.xml
Debug.Print objDocumentType.entities.length
Debug.Print objDocumentType.entities.Item(0).xml
End Sub
When you run this example and click the DocumentType button, you'll see the following output:
northwind:BOOKS <!DOCTYPE northwind:BOOKS SYSTEM "c:\Books.dtd"> 1 <!ENTITY copyright "">
Once again, you have created a reference to an IXMLDOMDocument interface. With this reference, you can use the doctype property to get a reference to an IXMLDOMDocumentType interface. Then you use the name and xml properties of the IXMLDOMDocumentType interface to get a node's name and its XML content. Notice that the parameter entity was not included in the entities collection.