Recommend a design pattern for a workflow applicat

Question

I am developing an application where the users can execute tasks / workflows. Each task is made up of a queue of actions to be executed. I want to be able to be able to have user input after the workflow is started.

Example:

• Task starts
  • Action1 starts
  • Action1 ends
  • Action2 starts
  • Action2 ends
  • Action3 needs user input (UI opens window to get user input)
  • Action3 gets user input
  • Action3 starts
  • Action3 ends
• Task ends

I am developing this i C# and I am aware of Workflow Foundation and tasks in C#. They may have what I need, but I am also interested in hearing about a design pattern for doing this from scratch.

Answer 1

I think the following articles can help you with the async task part:

The Task-based Asynchronous Pattern

TPL and Traditional .NET Asynchronous Programming

Answer 2

What you have described is the Sequence Workflow Pattern.

There are more Workflow Patterns at the Workflow Patterns initiative and in MSDN Magazine.