Activity Library in Workflow

Davin Martyn
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Introduction: Activities are the units of work that are composed to produce workflow based functionality. In WF4 activities explicitly declare their inputs and outputs via arguments. The Standard Activity Library are introduced a number of low level activities. These low level activities include Assign, Add to Collection, Remove for Collection, Clear for Collection, Invoked Method.

Create the Activity Library

Step 1 Open Visual Studio 2010.

Select File->New ->Project.
Select Activity Library.

After clicking Ok, the Activity1.Xaml Window opens.

ac1`.gif

Create a new Activity :

Step 2 : Go to Solution Explorer and right-click.

Go to Add-> New Item->CodeActivity.
Write the below code.

Code :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Activities;
using System.Activities.Runtime;
using System.Activities.Presentation;
namespace my_activity_library
{
    public sealed class CodeActivity1 : CodeActivity
    {
        [RequiredArgument]
        // Define an activity input argument of type string
        public InArgument<string> book { get; set; }
        protected override bool CanInduceIdle
        {
            get { return true; }
        }
        protected override void Execute(CodeActivityContext context)
        {
            // Obtain the runtime value of the Text input argument
            context.book(this.book.Get(context), this.book);
            string text = context.GetValue(this.book);
        }
        private void OnReadComplete(NativeActivityContext context, Bookmark bookmark, object state)
      {
        // Store the value returned by the host
        context.SetValue(this.book, state as string)
        }
    }
}

Step 3 : After the code we build the application and check the any error.

Step 4 : Add new Activity for the variables application.

Go to Solution Explorer and right-click.
Select Add-> New Item->Activity.

Step 5 : Now drag Activity from Toolbox.

Select Sequence , WritelLine activity.

Step 6 : Now define variable for the application.

Select Sequence Activity.
Go to create option and define variable name and scope.
Define Variable Type.

Step 7 : Now again go to Activity1.xaml option.

Define WriteLine property.
Give the Text Name.

Create the Test Project :

Step 8 : Go to Solution Explorer and right-click.

Go to Add->New Project.
Select ActivityLibrary.
Open Activity.cs and add the following code.

Code :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Activities;
using System.Activities.Runtime;
using System.Activities.Presentation;
namespace my_activity_library
{
    public sealed class CodeActivity1 : CodeActivity
    {
        public void ReadUserShouldDisplayAGreeting()
        {
            // Arrange
            const string firstBookmark = "FirsName";    // Intentional error - bookmark name misspelled
            const string lastBookmark = "LastName";
            const string expectedFirst = "First";
            const string expectedLast = "Last";
            const string expectedGreeting = "Hello " + expectedFirst + " " + expectedLast;
            var host = WorkflowApplicationTest.Create(new ReadUser());
            try
            {
                // Act
                // This code uses Workflow Episode support provided by extension methods from Microsoft.Activities

                // Run the workflow to the first idle point where a bookmark named "FirstName" exists
                host.TestWorkflowApplication.RunEpisode(firstBookmark, TestTimeout);
                // Resume the workflow with the first name
                    firstBookmark,      // The name of the bookmark to resume
                    expectedFirst,      // The value to resume the bookmark with
                    lastBookmark,       // The name of the next bookmark to wait for
                    TestTimeout);
                // Resume the workflow with the last name and run until complete, abort or timeout
                host.TestWorkflowApplication.ResumeEpisodeBookmark(lastBookmark, expectedLast, TestTimeout);
                // Assert
                // The text lines property captures text written with the WriteLine activity into an array of strings
                // There are three WriteLines plus an extra empty element at the end
                Assert.AreEqual(4, host.TextLines.Length);
                Assert.AreEqual(expectedGreeting, host.TextLines[2], "The greeting was not correct");
            }
            finally
            {
                host.Tracking.Trace();
            }
        }
    }
}

Step 9 : Now Press F5 and run the application.