Custom Activity in Workflow

Introduction: The Custom 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.

Step 1: Open Visual Studio and select the File option.

• Select New->Project->Workflow Console Application.
• Drag s Sequence activity and s WriteLine activity.
• Go to properties and write a Text "started application".

Let see how to create Sequential Workflow :

Step 2: Open Visual Studio 2010.

• Go to File->New->Project option.
• Select Visual C#->Workflow->.NET Framework 3.5.
• Select Sequential Workflow Console Application.
• Click OK .

After creating the Application, the designer window look like this:

Step 3 : Add an activity from Toolbox for Workflow.

• Add a Code activity in Workflow.
• Double click in codeActivity1 and write the following code.

Code :

namespace WorkflowLibrary1
{
    public sealed partial class Workflow1 : SequentialWorkflowActivity
    {
        public Workflow1()
        {
            InitializeComponent();
        }
        private void codeActivity1_ExecuteCode(object sender, EventArgs e)
        {
            Console.WriteLine("start 3.5 workflow");
        }
        private void codeActivity2_ExecuteCode(object sender, EventArgs e)
        {
            Console.WriteLine("finish 3.5 workflow");
        }
    }
}

Step 4 : Go to Workflow1.cs [Desaign] drag another codeActivity and write the below code.

Code :

namespace WorkflowLibrary1
{
    public partial class customActivity1 : SequenceActivity
    {
        public customActivity1()
        {
            InitializeComponent();
        }
        public static DependencyProperty MessageProperty = DependencyProperty.Register("Message", typeo
(string), typeof(customActivity1));
        [DescriptionAttribute("Message")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute
        (DesignerSerializationVisibility.Visible)]
        public string Message
        {

            get
            {
                return ((string)(base.GetValue(MessageProperty)));
            }
            set
            {
                base.SetValue(MessageProperty, value);
            }
        }
        private void codeActivity1_ExecuteCode(object sender, EventArgs e)
        {
            Console.WriteLine(this.Message);
        }
    }
}

Step 5 : Go to Solution Explorer and right-click.

• Select Project->Add Reference.
• Select SequentialWorkflowLibrary1.
• Press F6 to rebuild the solution.

Step 6 : Go to workflow1.xaml file.

• Drag a Interop activity below the WriteLine activity.
• Click browse and select Workflow1.
• Drag WriteLine activity below the Interop activity.
• Enter the Text property "Workflow finished".

Creating a Custom Activity:

Step 7: Go to Solution Explorer and right-click.

• Select WorkflowLibrary->Add->New Item.
• Select Activity and click on the Add option.
• Activity.cs designer option show.

Throwing an Exception:

Step 8: Open Custom.cs [Design] option.

• Drag Throw activity.
• Go to property options and select FaultType.
• Select mscorlib assembly->System namespace.
• Select InvalidProgramException.

Invoke Custome Activity:

Step 9 : Drag a WriteLine activity onto the Catch section.

• Write the Text property "Custome 3.5 activity".

Step 10 : Press F5 to run the application.