XOML is closely related to XAML, the Extensible Application Markup Language that is used to create user interface elements in Windows Presentation Foundation.
This resource kit links to tips and blog entries related to XOML. You will find a Notepad-like tool for seeing how XOML is implemented, hints for deploying a XOML-only workflow and reasons for using XOML files instead of compiled activities. If you have an XOML tip or resource that you would like to share, send me an e-mail and it will be added to this list.
XAMLPad is a tool for Windows Presentation Foundation that lets a user type in XAML code and see what would happen to the application. Mark Schmidt decided to do the same for Windows Workflow Foundation. The tool is called WFPad, and it works for both XAML and XOML.
Mark Schmidt talks about where XOML files fit into a WF project template, how to view these files and how to add XOML files to an existing workflow.
Here Jon Flanders blogs about storing root activities as XAML and XOML files rather than as compiled activities. Using the former method allows for better customization of workflows and for more dynamic "mix and match" of workflows to rules.
In XAML activation, a developer uses a serialized XOML file to create and run a workflow instance. Here Tom Lake discusses which workflow runtime methods to use for XAML activation and what to do if calling CreateWorkflow results in an exception.
Here Aleksey Savateyev provides a list comparing the standard out-of-the-box set of sequential workflow activities in Windows Workflow Foundation to BPEL constructs.
When updating Microsoft Message Queue activities for WF, Tomas Restrepo encountered a "strange issue." After designing a XOML-based workflow, closing the designer and reopening the workflow, an error message popped up indicating that the activity class needed to implement two static accessors -- which it already had. Find out what caused this and how to troubleshoot it.
This post from the Windows Workflow Foundation forum on MSDN outlines how to debug a XOML-only workflow. The key is to use the Breakpoints window in Visual Studio.
This was first published in October 2006