Validate Documents Using SAX

This example demonstrates how to create a simple SAX validator application in Microsoft® Visual Basic®. The application allows the user to select an XML file to be validated against an XSD schema file.

In this example, the SAX reader parses the sample XML file (books.xml), and writes validation results as output to a textbox control on the main form for the application.

The application is kept simple to demonstrate the fundamental principles involved. These principles include the following:

• Validating from within SAX applications, which differs from validating XML in DOM-based applications.
• Validating XML file input to a user-selectable XSD schema file.
• Using SAX error handler and SAX locator information to improve error reporting for your SAX application.

This topic is divided into the following sections.

• Overview of the SAX Validator Application
• Application Form (SAX Validator)
• Sample XSD Schema File (SAX Validator)
• MyValidator Class (SAX Validator)
• Run the Application (SAX Validator)
• How the SAX Validator Application Works

See Also

Sample XML File (books.xml)

Note   Currently, SAX-based validation only supports external XSD schemas. SAX-based validation using Document Type Definition (DTD) files is not supported.