Beginning ASP.NET 3.5 in C# 2008: From Novice to Professional, Second Edition

19.4. XML Validation

XML has a rich set of supporting standards, many of which are far beyond the scope of this book. One of the most useful in this family of standards is XSD (XML Schema Definition). XSD defines the rules to which a specific XML document should conform, such as the allowable elements and attributes, the order of elements, and the data type of each element.

When you're creating an XML file on your own, you don't need to create a corresponding XSD file—instead, you might just rely on the ability of your code to behave properly. While this is sufficient for tightly controlled environments, if you want to open your application to other programmers or allow it to interoperate with other applications, you should create an XSD document. ...