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Configuring the IfElse Activity

Given that fact that our numerical data can be processed in four unique manners, we will use an

IfElse activity to determine which web method of the service to invoke. When you drag an IfElse

activity onto your designer, you will automatically be given two branches. To add additional

branches to an IfElse activity, right-click the IfElse activity icon and select the Add Branch menu

option. Figure 26-13 shows the current WF designer (note that each branch and the entire IfElse

activity have been given proper names).

Each branch of an IfElse activity can contain any number of internal activities that represent

what should take place if the decision logic results in moving the flow of the application down a

given path. Before we add these subactivities, however, we first need to add the logic that allows the

WF engine to determine which branch to take by setting the Condition value to each IfElseBranch

activity. 

Recall that the Condition event can be configured to establish a code condition or a declarative

rule condition. The first example project in this chapter already illustrated how to create a code

condition, so in this example we will opt for rule conditions. Starting with the AddBranch, set the

Condition value to Declarative Rule Condition using the Visual Studio Properties window. Next,

click the ellipsis button for the ConditionName subnode, and click the New button from the result-

ing dialog box. Here, you are able to author a code expression that will determine the truth or falsity

of the current branch. For this first branch, the expression is as follows:

this.Operation == MathOperation.Add

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