PolicyActivity in Workflow

Introduction : The Policy activity represents a collection of rules. A rule consists of conditions and resulting actions. We can define a rule as an IF-THEN-ELSE statement with the condition corresponding to the IF and the action defining the behavior of THEN and ELSE clause. The      System.Workflow.Activities. The PolicyActivity class is a specialized workflow activity class that encapsulates a RuleSet. During execution time, the PolicyActivity retrieves the rules from the .rules file and executes the rules.

An action can do the following:

• Set a field or property on a workflow.
• Call a method on a workflow or objects in a workflow.
• Call static methods on types in referenced assemblies.
• Perform a Halt or an Update statement.

Step 1 : Open Visual Studio 2010.

• Select File->New->Project.
• Select Workflow->Sequential Workflow.
• Click OK.

Step 2 : Drag PolicyActivity from Toolbox.

• Right-click on the   PolicyActivity.
• Select the RuleSetReference option.

Step 3 : Click the RuleSetReference property and open Rule Editor.

 
Step 4 : Click New RuleSet.

Step 5 : Add condition for PolicyActivity.

• Select New->Add Rule option.
• Write Rule, Condition, Action.

Condition :

this.orderValue >= 100 && this.orderValue <=200, then

Action :
this.discount = 0.1 (10%)

Step  6 :  Now go to Workflow1.cs file.

• Write a code for application.

Code :

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Collections;
using System.Linq;
using System.Workflow.ComponentModel.Compiler;
using System.Workflow.ComponentModel.Serialization;
using System.Workflow.ComponentModel;
using System.Workflow.ComponentModel.Design;
using System.Workflow.Runtime;
using System.Workflow.Activities;
using System.Workflow.Activities.Rules;
using System.Collections.Generic;
using System.Threading;
namespace policy
{
    public sealed partial class Workflow1 : SequentialWorkflowActivity
 {
        public Workflow1()
        {
            InitializeComponent();
        }
         public void setdiscount_closed(object sender, ActivityExecutionStatusChangedEventArgs e)
|        {
            Console.WriteLine("discount on orderValue{0}is {1}", orderValue, discount);
        }
        public double orderValue { get; set; }
        public double discount { get; set; }
    }
}


Step 7 : Go to Program.cs file and add Namespace.

• Go to Solution Explorer->Right-click.

• Select Add Reference option.

• Add System.Workflow.Runtime, System.Workflow.ComponentModal.

•  Write a code.

Code :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Workflow.Activities;
using System.Workflow.Runtime;
using System.Workflow.ComponentModel;
using System.Threading;
namespace ConsoleApplication1
{
    class Program
    {
        static AutoResetEvent waitHandle = new AutoResetEvent(false);
        static void Main(string[] args)
        {
            using (WorkflowRuntime wr = new WorkflowRuntime())
            {
                wr.StartRuntime();
                    wr.WorkflowCompleted+= new EventHandler<WorkflowCompletedEventArgs>(wr_WorkflowCompleted);
               Dictionary<string, object> param = new Dictionary<string, object>();
                param.Add("orderValue", 120.5);
                WorkflowInstance wi = wr.CreateWorkflow(typeof(ConsoleApplication1.Program),param);
                wi.Start();
                waitHandle.WaitOne();
                 wr.StopRuntime();
            }
            Console.Read();
        }
       
    }
}

Step 8 : Press F5 to run the application.