This document discusses workflows and activities. It defines a workflow as a set of activities that describes a real-world process. Activities store data using variables, arguments, and expressions. Workflows define the order and dependencies of activities from start to finish. There are two main types of workflow models - sequential and state machine. The document also discusses activity life cycles, passing parameters in and out of workflows, and how to create custom reusable activities.

2. WHY WORKFLOWS ?
• Programming model
• Enabling workflow within line-of-business applications
• User-interface page flows
• Document-centric workflows
• Human workflows
• Composite workflows for service-oriented applications
• Business rule-driven workflows
• Workflows for systems management

3. WHAT IS WORKFLOW ?
• A workflow is a set of elemental units
• called activities
• Activities describes a real-world process
• Activity Stores Data using
• Variable
• Argument
• Expression
• Describing the order of execution and dependent relationship
• Work passes through the model from start to finish

4. WORKFLOW MODELS
 Sequential Activity Workflow
 start To end
 No Go back
 One after the other
 State machine Activity Workflow
 Only States
 Transitions
 when true

5. ACTIVITY OVERVIEW
• Developed as a CLR type
• Activity
• An abstract base class used to create composite activities
• Code Activity
• An abstract class for creating a custom activity with imperative behavior
defined with the Execute method
• Async Code Activity
• Abstract Class that manages asynchronous code activity execution from start
to completion
• Native Activity
• An Abstract base class for custom activities that implement execution logic
using the Execute method, which has full access to the runtime’s features.

6. ACTIVITY LIFE CYCLE
• Activity Context
• Classes that represent the execution environment of an activity
• Starts with Executing
• Closed
• The activity has completed its work and exited
• Canceled
• The activity has gracefully abandoned its work and exited. Work is not
explicitly rolled back when this state is entered
• Faulted
• The activity has encountered an error and has exited without completing its
work

7. WORK FLOW RUNTIME
• is the environment in which workflows execute
• Few methods of executing
• WorkflowInvoker
• which invokes the workflow like a method.
• WorkflowApplication
• explicit control over the execution of a single workflow instance.
• WorkflowServiceHost
• message-based interactions in multi-instance scenarios.

8. WORKFLOW EXECUTION
Invoker Method
WorkflowApplication
• Events
• Completed
• Aborted
• Idle

10. PASSING PARAMETERS - IN
Property Method
IDictionary Method

11. PASSING PARAMETERS - OUT
Using Application
Using Invoker

12. CUSTOM ACTIVITIES
• Set of Reusable Activities
• Apply Same Workflow Rules
• Can have design interface
• Can have validation
• Override Metadata Cache