As I demonstrated in chapter 16 of my WF book, one of the authoring modes that you can use to define the workflow model is the no-code (markup-only) mode. Using this authoring mode, you define the workflow model in an XML file using XAML syntax.
If you try to do this manually in Visual Studio without the aid of a designer, it is fairly tedious and it can be error prone since there’s no Intellisense support. At least until now. Microsoft has now released a workflow XAML schema that makes this process a little easier.
After downloading the file, you unzip it into the default location:
%ProgramFiles%\Microsoft Visual Studio 8\Xml\Schemas
Once the schema file (XamlWorkflow2006.xsd) is installed into the correct directory, Visual Studio will provide Intellisense within it’s XML editor when you edit workflow markup files (.xoml).
Keep in mind that this won’t work for any custom workflow types that you’ve defined and wish to reference. This schema only has knowledge of the standard workflow types provided by MS. However, if there are types that you frequently use, you can modify this schema file yourself in order to provide Intellisense.