For a long time I preferred Altova’s XMLSpy as an XSD editor. I especially like its graphical schema display – it shows the structure of your schema in a very intuitive way. However, I have recently discovered that Visual Studio 2005 is very capable XSD editor too, just not that much graphical.

While editing one of my XML files I decided to change the schema and didn’t want to leave the IDE so I just started typing directly in Visual Studio 2005 XML editor. It turns out that IDE XML validation goes way beyond what you would expect. I discovered this by adding a new type (a new element) that had the same name as one of the existing elements.

And then I got a very, very detailed and instructive warning – if you name two elements the same, and only change number/kind of attributes and number/nesting of inner elements, it makes parsing and validating such elements hard, because parser cannot deduce what the element is just by its name.

This is very cool. It’s not complicated to validate XSD rigidly according to its schema, but it’s definitely complicated/extra work to provide meaningful warnings like this one – hard to implement for IDE developers, but good and useful for us XML developers.