CompensatableSequence Activity in Workflow

Introduction : The CompensateSequence Activity will provide compensation only if there is any error thrown. The CompensatableSequence Activity class inherits from Sequence Activity, it can contain any number of child activities that execute in order. Compensation logic is similar to a transaction. The difference is that a transaction locks the database until all updates are done, making it only suitable for short durations. A compensate action is used in long running transactions to undo the original transaction that was already committed.

• Compensate sequence class : public sealed class.
• CompensatableSequence Activity : Sequence Activity, ICompensatable Activity.

Step 1 : Open Visual Studio 2011.

• Go to File->New->Project.
• Select Sequential Workflow Console Application.

Step 2 : Now drag the activity from Toolbox.

• Select CompensatableSequenceActivity.
• Select Code Activity and Delay Activity below the CompensatableSequence Activity.

Step 3 : Right-click on CompensatableSequence Activity and go to Properties option.

• Give the Enabled Condition is "True".

Step 4 : Click in CompensatableSequence Activity and select View Compensation Handler because we can define the Executecode.

• Define the CodeActivity1 event inside the property of CodeActivty2.

Step 5 : Now go to the Workflow1.cs[Design] and select Sequential Workflow Application and right-click.

• Define the Completed and Initialized property.

Step 6 : Go to Workflow1.cs and write the below code.

Code :

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Collections;
using System.Collections.Generic;
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;
namespace WorkflowConsoleApplication21
{
    public sealed partial class Workflow1 : SequentialWorkflowActivity
    {
        public Workflow1()
        {
            InitializeComponent();
        }
        private void codeActivity1_ExecuteCode(object sender, EventArgs e)
        {
            Console.WriteLine("hi my workflow application");
            Console.WriteLine("Prerss Exist to application");
            Console.WriteLine("activity processing......");
            Console.WriteLine("activity execurte.....");
            Console.ReadLine();
        }
        private void delayActivity2_InitializeTimeoutDuration(object sender, EventArgs e)
        {
            DelayActivity delay = sender as DelayActivity;
            if (delay != null)
            {
                delay.TimeoutDuration = new TimeSpan(0, 0, 5);
            }
        }
        private void codeActivity2_ExecuteCode(object sender, EventArgs e)
        {
            Console.WriteLine("namstey");
            Console.ReadLine();
        }
    }
}

Step 7 : Select Solution Explorer and click program.cs option and define the below code.

Code :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Workflow.Runtime;
using System.Workflow.Runtime.Hosting;
namespace WorkflowConsoleApplication21
{
    class Program
    {
        static void Main(string[] args)
        {
            using (WorkflowRuntime workflowRuntime = new WorkflowRuntime())
            {
                AutoResetEvent waitHandle = new AutoResetEvent(false);
                workflowRuntime.WorkflowCompleted += delegate(object sender, WorkflowCompletedEventArgs e) { waitHandle.Set(); };
                workflowRuntime.WorkflowTerminated += delegate(object sender, WorkflowTerminatedEventArgs e)
                {
                    Console.WriteLine(e.Exception.Message);
                    waitHandle.Set();
                };
                WorkflowInstance instance = workflowRuntime.CreateWorkflow(typeof(WorkflowConsoleApplication21.Workflow1));
                instance.Start();
                waitHandle.WaitOne();
            }
        }
    }
}

Step 8 : Now we Press F5 and run the application.