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70 Part I Introducing Windows Workflow Foundation (WF)

6. In the Name field, type the name of your project or application.

7. In the Location field, type the file system location where you would like your project files

stored.

8. If the Create Directory For Solution check box is not already selected, select it.

9. Click OK. Visual Studio 2005 will now create the basic project for you and bring up the

workflow visual designer user interface.

As with the sequential workflow application, Visual Studio is now ready for us to build a state￾machine workflow. We’re not quite ready to actually build a state-machine workflow at this

point in the book. Why? Because we need to trigger the events that cause the workflow to

change state. To do that, we’ll need to understand how workflow instances communicate with

their host applications so that our host application can perform the trigger actions. We’ll

begin looking at host and workflow communication in Chapter 8, “Calling External

Methods,” but it’s in Chapter 10, “Event Activities,” that we learn what we need to know

to drive state-machine workflows.

Chapter 4 Introduction to Activities and Workflow Types 71

Chapter 4 Quick Reference

To Do This

Select the appropriate workflow type Model your system, and look closely at what is controlling

the process. If the workflow is controlling the process,

select a sequential workflow model. If external inputs are

controlling the workflow, select a state-machine workflow.

If complex behavior is to be modeled, a rules-based

approach might be the best. Often a combination of

workflow types will be necessary.

Build a sequential workflow application Start Visual Studio 2005, and select the New and then

Project menu items from the main File menu. From the

resulting New Project dialog box, select the Workflow node

from the Visual C# subtree shown in the Project Types

pane. From the Templates pane, select either the Sequen￾tial Workflow Console Application or the Sequential

Workflow Library type.

Build a state-machine workflow application Follow the steps for building a sequential workflow appli￾cation until you choose the template. In the Templates

pane, select either the State Machine Workflow Console

Application or the State Machine Workflow Library type.

Build a rules-based workflow application Create a sequential workflow application, and then skip to

Chapter 12 to learn how to apply the Policy or rule

condition.

73

Chapter 5

Workflow Tracking

After completing this chapter, you will be able to:

■ Describe workflow-pluggable services

■ Create an event tracking database and populate it with tables and scripts

■ Activate the event-tracking service

■ Create a custom tracking profile

■ View your workflow's tracking information

So far we’ve seen the basic objects that workflows are built from and controlled by. We build

workflow tasks from activities, which when executing are managed by a WorkflowInstance

object. Workflow instances are queued and controlled by the WorkflowRuntime. But Windows

Workflow Foundation (WF) doesn’t just provide us with objects—it also provides us with

services that work alongside our objects.

Pluggable Services

Workflow services are additional software functions that your workflows can, and will, use to

complete their tasks. Some of the services are optional, like the tracking service we’ll work

with in this chapter. Other services are required for your workflow to execute at all.

Workflow services are pluggable. A pluggable service is a service that can be selected a la carte

to perform specific tasks. For example, there are services that manage threading, tracking,

transactions, and so forth. You select the service that’s right for your workflow. You can even

create your own.

So what do these services look like? What do they do for us? Table 5-1 lays out the available

base services and gives you a better idea which services are available and what they do.