SharePoint Workflows and Visual Studio 2005
When you need Workflows that will have a larger impact than single-instance workflows, you won't be able to use the SharePoint Designer tool. Visual Studio 2005 (with the .NET Framework 3.0 properly installed extensions) has a designer for WF applications that lets you build sequential and state machine workflows, build your own custom activities, and much more. You can utilize this functionality to build your own SharePoint workflows by downloading a toolkit from Microsoft.
The SharePoint Server 2007 SDK includes the updated SDK as well as the Enterprise Content Management (ECM) Starter Kit. Included in the ECM starter kit are Visual Studio 2005 templates for creating SharePoint-specific sequential and state-machine workflows. In addition, the starter kit includes sample code for many different kinds of workflow scenarios.
Workflow Classes
While editing workflows using Visual Studio 2005 or SharePoint Designer might be helpful, many developers will want direct access to the Workflows that are running within the context of Windows SharePoint Services list items. This can be accomplished by code running on the SharePoint server through the SPWorkflow class, the entry point into the SharePoint-specific implementation of Windows Workflow Foundation. The following is a list of a few of the properties of the SPWorkflow class that can be queried at runtime by developers:
- Author, the initiator of the workflow (integer).
- AuthorUser, an instance of the SPUser class representing the author of the workflow.
- HistoryList, a reference to an instance of the SPList object that contains the entire history of the workflow. This is useful for developers wishing to render the status of an open workflow, or the history of completed workflows.
- IsCompleted, a Boolean indicating whether the workflow has been completed.
- Tasks, an instance of the SPWorkflowTaskCollection class containing the list of tasks associated with the current workflow.
Some other useful classes include the SPWorkflowTemplateCollection class, which represents the list of workflow templates installed on a given site. The SPWorkflowTemplate class represents a single workflow template. Remember that a workflow template is the definition of the structure of the workflow, while an instance of a workflow is a running copy of that template. Finally, one of the most powerful SharePoint workflow classes is the SPWorkflowManager class that can start, run, or cancel workflows and query the list of active workflows running for a given item. All of these classes are documented in the WSS SDK available online at msdn2.microsoft.com/en-us/library/aa902527.aspx.
