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Windows Workflow

SharePoint Server 2007 provides various out-of-the-box workflows that require no additional attention before using. These workflows include Approval (routes a document for approval), Collect Feedback (routes a document for review), Collect Signatures (gathers signatures), Disposition Approval (manages document expiration and retention), Group Approval (similar to the Approval workflow, but designed specifically for East Asian markets), Translation Management (manages document translation), and Issue Tracking (manages the issue tracking process by creating tasks for active issues assigned to users).

Many processes are very specific to an individual company's needs. Therefore, the WorkFlow Foundation provides an extensible infrastructure that can be used to create sophisticated workflows. WF provides a powerful platform with a unified programming model, and it works with familiar developmental tools such as Visual Studio 2005. Less powerful SharePoint workflows also can be created with SharePoint Designer (formally FrontPage), a web design and customization tool that allows users to create workflows without writing any code.

Windows SharePoint Services (WSS) 2007 is the first Microsoft server that has native support for the Windows WorkFlow Foundation (WF). The integration of WF and the 2007 release of SharePoint provides an infrastructure that drives processes around SharePoint's strong suit: collaboration and sharing of information. This release focuses on document-centric workflows, the procedures that a particular document goes through in its lifecycle (be they reviewing, editing, or approval). The new edition enables you to attach and run a process directly in a SharePoint document or list item. Additionally, the workflows within SharePoint spotlight human-based endeavors, tasks driven by human interaction as opposed to static, automated programmatic steps.

A Useful Case Study
A standard Visual Studio installation lacks the necessary tools to work with the WorkFlow Foundation, so to put things in motion you must install the Visual Studio 2005 extensions for .NET Framework 3.0 (Windows Workflow Foundation). The extensions provide the required references to the Foundation assemblies, the essential Activities needed, as well as the WorkFlow designer within Visual Studio and a number of project templates. (Keep in mind that you must install DotNet Framework 3.0 as a prerequisite to working with WF.)

A Visual Studio 2005 extension that is compatible with the WorkFlow Foundation to work with SharePoint is available. Note that this extension is not required if you are developing workflows for SharePoint (the extension makes a new template to initialize a project).

The first step in creating a workflow for SharePoint is crafting a new project in Visual Studio 2005 based in the Sequential Workflow Library (or in the State Machine Workflow Library, if you are making a state machine workflow) and assigning it a name. Visual Studio will generate the necessary code and configuration files. Add a reference to Windows SharePoint Services (Microsoft.SharePoint.dll) and, if you need to work with Microsoft Office SharePoint Server, a reference to Microsoft Office SharePoint Server component (microsoft.sharepoint.portal.dll). This establishes references to the object model of SharePoint, opening the door to interactions with it.

Although it's not compulsory, it simplifies coding if you write directives to the next namespaces in the code behind file, for example:

Finally, you need to add an activity to the Visual Studio toolbox. Using the context menu (right-click into the toolbox), select Choose items and in the .NET Framework Components tab, check the OnWorkflowActivated activity to activate it in the toolbox. This activity is indispensable for running workflows in SharePoint.

The following example builds a simple workflow that illustrates the lifecycle of a WF within SharePoint: initializing the workflow, transporting information from SharePoint, processing it, and feeding it back to WSS.

*This is an example WorkFlow in the Visual Studio WorkFlow Designer

You initialize the process by creating the workflow using the WorkFlow Designer in Visual Studio. The opening activity is always the OnWorkflowActivated for workflows in SharePoint. Next, install a While activity with a Code Activity inside to process the information. Finally, install another Code Activity to return information to SharePoint. Bear in mind that this is not a functional workflow you would use in a business application, but a demonstration of each part of the interaction between WF and SharePoint.

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