VWF310: Encapsulate Custom Business Processes with Custom

WF Activities

Brian Noyes

IDesign Inc (www.idesign.net)

brian.noyes@idesign.net

About Brian

• Chief Architect, IDesign Inc. (www.idesign.net) • Microsoft Regional Director / MVP• Publishing

● Developing Applications with Windows Workflow Foundation, LiveLessons training DVD, June 2007.

● Smart Client Deployment with ClickOnce, Addison Wesley, January 2007

● Data Binding in Windows Forms 2.0, Addison Wesley, January 2006● MSDN Magazine, MSDN Online, CoDe Magazine, The Server

Side .NET, asp.netPRO, Visual Studio Magazine• Speaking

● Microsoft TechEd US, Europe, Malaysia, Visual Studio Connections, DevTeach, INETA Speakers Bureau, MSDN Webcasts

• Participates in Microsoft Design Reviews• E-mail: brian.noyes@idesign.net• Blog: http://briannoyes.net

Agenda

• Activities Overview

• Custom Activities Overview

• Custom Simple Activities

• Custom Composite Activities

WF Activities Overview

• Activities are the building blocks of workflows

• Activities can be simple or composite● Simple: Does not contain child activities, just

executable code● Composite

• Contains child activities• Can schedule children for proper execution order

through the scheduler queue

Agenda

• Activities Overview

• Custom Activities Overview

• Custom Simple Activities

• Custom Composite Activities

Custom Activities

• Reasons for Custom Activities● Encapsulation

• Composite activities to avoid duplication

● Domain specific activities• Vertical market

● Advanced control flow• Specific flow patterns• Multithreading

Activities: An Extensible Approach

OOB activities, workflow types, base types

General-purpose Activity libraries define workflow constructs

Create/Extend/ Compose activities

App-specific building blocks

First-class citizens

Base ActivityLibrary

Custom Activity Libraries

Author new activity

Extend activity

Compose activitiesOut-of-Box

Activities

Vertical-specific activities & workflows

Best-practice IP & Knowledge

Domain-Specific Workflow Packages

Compliance

RosettaNet

CRM

IT Mgmt

Custom Activities

• Author custom activity class (Required)● Derives from Activity or other Base Activity

Library class● CompositeActivity for composites

• Define related classes (Optional)● Executor● Validator● Designer● Toolbox Item

Activity Attributes

• Designer● Specify design time behavior of activity

• Validator● Design and runtime checking to make sure activity is used correctly

• CodeGenerator● Perform compile time code generation for the activity

• Serializer● Serializes activity metadata to markup

• ToolboxItem● Determine icon in Toolbox

• SupportsTransaction● Enable transaction management and propagation in activity

• SupportsExceptionHandlers● Allows hookup of exception handler activities

Activity Definition

• Base class : Activity• Add 0..many DependencyProperty

● Centralized repository of workflow state● Define the properties available on the activity● Faster serialization than normal properties and fields● Accessible from child activities

• Add 0..many wrapper (normal) properties● Use base class GetValue/SetValue methods for

persistence model● Serializable types if persistence enabled

Activity Lifecycle

Initialized Executing Closed

Activity Lifecycle

Initialized Executing ClosedUninitializing

Canceling

Faulting

Compensating

Dependency Properties

• Three kinds● Attached● Data binding● Metadata

• Add semantics over normal properties

• Greater scope than normal properties● Stored through static state bag on base class

Agenda

• Activities Overview

• Custom Activities Overview

• Custom Simple Activities

• Custom Composite Activities

Simple Activity Definition

• Create class that inherits Activity base class• Override base class Execute method

• Do activity work from Execute• Can also override Initialize / Uninitialize• Use activity execution context to access

services

protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext) { return base.Execute(executionContext); }

Agenda

• Activities Overview

• Custom Activities Overview

• Custom Simple Activities

• Custom Composite Activities

Composite Activity Types

• Basic● Like a user control in Windows Forms or ASP.NET● Container for other pre-defined activities● Drag and drop in the designer● Default rendering shows all child activities when used in

a workflow● Expose properties as needed

• Advanced● Define custom child activity types or scheduling

algorithms● Define custom design time rendering and behavior

Advanced Composite Control Flow

• Enqueue child activities in desired order● Use ActivityExecutionContextManager.

CreateExecutionContext● Use ActivityExecutionContext.ExecuteActivity● Handle Closed event of child activities to

decide on own composite activity completion

Resources

• Essential Windows Workflow Foundation, Dharma Shukla and Bob Schmidt, Addison Wesley

• Pro WF, Bruce Bukovics, Apress• Microsoft Windows Workflow Foundation Step by Step, Kenn Scribner,

Microsoft Press• Build Custom Activities to Extend the Reach of Your Workflows, Matt

Milner, MSDN Magazine, Dec 2006 http://msdn2.microsoft.com/en-us/magazine/cc163504.aspx

• Windows Workflow Foundation: Creating a Custom Composite Activity, Morgan Skinner, MSDN Online, http://msdn2.microsoft.com/en-us/library/aa480200.aspx

• Developing Applications with Windows Workflow Foundation, Brian Noyes, Addison Wesley LiveLesson

• Email: brian.noyes@idesign.net• Blog: http://www.softinsight.com/bnoyes

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