Using a Parallel activity in a custom Composite activity (Beta 2)

Using a Parallel activity in a custom Composite activity (Beta 2)

• NewbieElliott

  Thanks for your reply, Arjun.

  The original project I wrote to test the functionality was heavily edited (I went on to play with something else), so by the time I heard back from you I couldn't refer to the original code. Having read that you didn't experience the same issue I initially saw, I just went back and rewrote the activity and workflow from scratch (code follows).

  What I believe to have been the problem involves the Closed event handler hookup and the call to execute the activity (on the child context). As I recall, my original custom activity had syntax for these operations similar to:

  Activity childActivity = this.EnabledActivities[_index];

  if (childActivity != null)

  {

  ActivityExecutionContext childContext = context.ExecutionContextManager.CreateExecutionContext(childActivity);

  childActivity.Closed += OnClosed;

  childContext.ExecuteActivity(childActivity);

  }

  Using the above syntax, I am able to make my new activity fail in the same manner it failed initially. Changing the syntax to:

  Activity childActivity = this.EnabledActivities[_index];

  if (childActivity != null)

  {

  ActivityExecutionContext childContext = context.ExecutionContextManager.CreateExecutionContext(childActivity);

  childContext.Activity.Closed += OnClosed;

  childContext.ExecuteActivity(childContext.Activity);

  }

  The difference is that instead of referring directly to the Activity about to execute (childActivity in this case), the code must access the Activity as a property of the ActivityExecutionContext. While I understand some possible causes for this behavior, it's somewhat non-obvious. It implies to me that the child context is operating on a copy of (or at least an indirect reference to) the child activity, and does not expose a reference to the actual instance. Perhaps I've missed something in the documentation about this - please let me know if I have.

  Here's the complete code, and thanks again...

  CustomParallelActivity.cs

  using System;

  using System.ComponentModel;

  using System.ComponentModel.Design;

  using System.Collections;

  using System.Drawing;

  using System.Workflow.ComponentModel;

  using System.Workflow.ComponentModel.Design;

  using System.Workflow.ComponentModel.Compiler;

  using System.Workflow.ComponentModel.Serialization;

  using System.Workflow.Runtime;

  using System.Workflow.Activities;

  using System.Workflow.Activities.Rules;

  namespace ActivityTest

  {

  [Designer(typeof(SequentialActivityDesigner))]

  public partial class CustomParallelActivity: CompositeActivity

  {

  private int _index = 0;

  public CustomParallelActivity()

  {

  InitializeComponent();

  }

  protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)

  {

  StartActivityAtIndex(_index, executionContext);

  return ActivityExecutionStatus.Executing;

  }

  private void StartActivityAtIndex(int activityIndex, ActivityExecutionContext context)

  {

  if (this.EnabledActivities.Count > _index)

  {

  if (context != null)

  {

  Activity childActivity = this.EnabledActivities[_index];

  if (childActivity != null)

  {

  ActivityExecutionContext childContext = context.ExecutionContextManager.CreateExecutionContext(childActivity);

  childContext.Activity.Closed += OnClosed;

  childContext.ExecuteActivity(childContext.Activity);

  Console.WriteLine("Requested execution for activity '{0}'", childContext.Activity.Name);

  }

  }

  }

  else

  {

  context.CloseActivity();

  }

  }

  void OnClosed(object sender, ActivityExecutionStatusChangedEventArgs e)

  {

  // Cast the sender as an execution context

  ActivityExecutionContext context = sender as ActivityExecutionContext;

  if (context != null)

  {

  // Get the closed activity's context and unload it

  Activity childActivity = e.Activity;

  if (childActivity != null)

  {

  ActivityExecutionContext childContext = context.ExecutionContextManager.GetExecutionContext(childActivity);

  if (childContext != null)

  {

  childContext.Activity.Closed -= OnClosed;

  context.ExecutionContextManager.CompleteExecutionContext(childContext);

  }

  // Move the index ahead to the next enabled activity in sequence.

  _index++;

  // Attempt to start the next activity

  StartActivityAtIndex(_index, context);

  }

  else

  {

  throw new ArgumentException("Cannot proceed. Current context has a null Activity.");

  }

  }

  else

  {

  throw new ArgumentException("Argument must be castable to type ActivityExecutionContext.", "sender");

  }

  }

  private void codeActivity3_ExecuteCode(object sender, EventArgs e)

  {

  Console.WriteLine("The parallel activity is about to execute...");

  }

  private void codeActivity1_ExecuteCode(object sender, EventArgs e)

  {

  Console.WriteLine("branch #1 of the parallel activity is executing...");

  }

  private void codeActivity2_ExecuteCode(object sender, EventArgs e)

  {

  Console.WriteLine("branch #2 of the parallel activity is executing...");

  }

  }

  }

  CustomParallelActivity.Designer.cs

  using System;

  using System.ComponentModel;

  using System.ComponentModel.Design;

  using System.Collections;

  using System.Drawing;

  using System.Reflection;

  using System.Workflow.ComponentModel;

  using System.Workflow.ComponentModel.Design;

  using System.Workflow.ComponentModel.Compiler;

  using System.Workflow.ComponentModel.Serialization;

  using System.Workflow.Runtime;

  using System.Workflow.Activities;

  using System.Workflow.Activities.Rules;

  namespace ActivityTests

  {

  public partial class CustomParallelActivity

  {

  #region Designer generated code

  /// <summary>

  /// Required method for Designer support - do not modify

  /// the contents of this method with the code editor.

  /// </summary>

  private void InitializeComponent()

  {

  this.CanModifyActivities = true;

  this.parallelActivity1 = new System.Workflow.Activities.ParallelActivity();

  this.sequenceActivity1 = new System.Workflow.Activities.SequenceActivity();

  this.sequenceActivity2 = new System.Workflow.Activities.SequenceActivity();

  this.codeActivity1 = new System.Workflow.Activities.CodeActivity();

  this.codeActivity2 = new System.Workflow.Activities.CodeActivity();

  this.codeActivity3 = new System.Workflow.Activities.CodeActivity();

  //

  // parallelActivity1

  //

  this.parallelActivity1.Activities.Add(this.sequenceActivity1);

  this.parallelActivity1.Activities.Add(this.sequenceActivity2);

  this.parallelActivity1.Name = "parallelActivity1";

  //

  // sequenceActivity1

  //

  this.sequenceActivity1.Activities.Add(this.codeActivity1);

  this.sequenceActivity1.Name = "sequenceActivity1";

  //

  // sequenceActivity2

  //

  this.sequenceActivity2.Activities.Add(this.codeActivity2);

  this.sequenceActivity2.Name = "sequenceActivity2";

  //

  // codeActivity1

  //

  this.codeActivity1.Name = "codeActivity1";

  this.codeActivity1.ExecuteCode += new System.EventHandler(this.codeActivity1_ExecuteCode);

  //

  // codeActivity2

  //

  this.codeActivity2.Name = "codeActivity2";

  this.codeActivity2.ExecuteCode += new System.EventHandler(this.codeActivity2_ExecuteCode);

  //

  // codeActivity3

  //

  this.codeActivity3.Name = "codeActivity3";

  this.codeActivity3.ExecuteCode += new System.EventHandler(this.codeActivity3_ExecuteCode);

  //

  // CustomParallelActivity

  //

  this.Activities.Add(this.codeActivity3);

  this.Activities.Add(this.parallelActivity1);

  this.Name = "CustomParallelActivity";

  this.CanModifyActivities = false;

  }

  #endregion

  private ParallelActivity parallelActivity1;

  private SequenceActivity sequenceActivity1;

  private CodeActivity codeActivity1;

  private SequenceActivity sequenceActivity2;

  private CodeActivity codeActivity2;

  private CodeActivity codeActivity3;

  }

  }

  
  
  

• Fekih Mehdi

  There was nothing really to resolve. Mainly I was pointing out that some of the BETA 2 features resulted in an API behavior that was unintuitive to users. I haven't changed my mind about it, but I'm not losing any sleep over it, either - particularly since this was, like, a year or so ago...

  Are you just in the process of touching all these old, unresolved issues to see if anyone's still tracking them or something If so, feel free to close the thread. Whole civilizations have risen and crumbled since I wrote that post; I've even interviewed with your team in the intervening months.

  Thanks for checking, anyway.

  Jared

  
  
  

• prasad knv

  You're more dedicated than I am, Angel.

  {slaps self on forehead}

  That must be why I didn't get the job - I distinctly remember scoffing when asked if I would be willing to cull through presumably dead forum threads looking for unresolved issues as much as a year after they were last touched.

  Thanks for checking; go have a weekend!

  Jared

  
  
  

• Ken Harris

  Hi,

  Hopefully you've reached a resolution. If for some reason you have not, please make another post.

  Thanks!
  Angel

  
  
  

• GraemeE

  Jared,

  I tried to repro this scenario and things seem to work fine for me. I've pasted my code below - maybe you could compare it to your version I'd be interested in knowing the difference and if there are any potential bugs.

  Activity1.cs

  using System;

  using System.ComponentModel;

  using System.ComponentModel.Design;

  using System.Collections;

  using System.Drawing;

  using System.Workflow.ComponentModel;

  using System.Workflow.ComponentModel.Design;

  using System.Workflow.ComponentModel.Compiler;

  using System.Workflow.ComponentModel.Serialization;

  using System.Workflow.Runtime;

  using System.Workflow.Activities;

  using System.Workflow.Activities.Rules;

  //NOTE: When changing the namespace; please update XmlnsDefinitionAttribute in AssemblyInfo.cs

  namespace WorkflowConsoleApplication5

  {

  public partial class Activity1 : System.Workflow.ComponentModel.CompositeActivity

  {

  public Activity1()

  {

  InitializeComponent();

  }

  protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)

  {

  ActivityExecutionContext ex = executionContext.ExecutionContextManager.CreateExecutionContext(this.EnabledActivities[0]);

  ex.ExecuteActivity(ex.Activity);

  ex.Activity.Closed += new EventHandler<ActivityExecutionStatusChangedEventArgs>(Activity_Closed);

  return base.Execute(executionContext);

  }

  void Activity_Closed(object sender, ActivityExecutionStatusChangedEventArgs e)

  {

  ActivityExecutionContext context = sender as ActivityExecutionContext;

  //custom close logic here.

  }

  private void codeActivity1_ExecuteCode(object sender, EventArgs e)

  {

  Console.WriteLine("foo");

  }

  }

  }

  Activity1.Designer.cs

  using System;

  using System.ComponentModel;

  using System.ComponentModel.Design;

  using System.Collections;

  using System.Drawing;

  using System.Reflection;

  using System.Workflow.ComponentModel;

  using System.Workflow.ComponentModel.Design;

  using System.Workflow.ComponentModel.Compiler;

  using System.Workflow.ComponentModel.Serialization;

  using System.Workflow.Runtime;

  using System.Workflow.Activities;

  using System.Workflow.Activities.Rules;

  namespace WorkflowConsoleApplication5

  {

  public partial class Activity1

  {

  #region Designer generated code

  /// <summary>

  /// Required method for Designer support - do not modify

  /// the contents of this method with the code editor.

  /// </summary>

  private void InitializeComponent()

  {

  this.CanModifyActivities = true;

  this.parallelActivity1 = new System.Workflow.Activities.ParallelActivity();

  this.sequenceActivity3 = new System.Workflow.Activities.SequenceActivity();

  this.sequenceActivity4 = new System.Workflow.Activities.SequenceActivity();

  this.codeActivity1 = new System.Workflow.Activities.CodeActivity();

  this.codeActivity3 = new System.Workflow.Activities.CodeActivity();

  //

  // parallelActivity1

  //

  this.parallelActivity1.Activities.Add(this.sequenceActivity3);

  this.parallelActivity1.Activities.Add(this.sequenceActivity4);

  this.parallelActivity1.Name = "parallelActivity1";

  //

  // sequenceActivity3

  //

  this.sequenceActivity3.Activities.Add(this.codeActivity1);

  this.sequenceActivity3.Name = "sequenceActivity3";

  //

  // sequenceActivity4

  //

  this.sequenceActivity4.Activities.Add(this.codeActivity3);

  this.sequenceActivity4.Name = "sequenceActivity4";

  //

  // codeActivity1

  //

  this.codeActivity1.Name = "codeActivity1";

  this.codeActivity1.ExecuteCode += new System.EventHandler(this.codeActivity1_ExecuteCode);

  //

  // codeActivity3

  //

  this.codeActivity3.Name = "codeActivity3";

  this.codeActivity3.ExecuteCode += new System.EventHandler(this.codeActivity1_ExecuteCode);

  //

  // Activity1

  //

  this.Activities.Add(this.parallelActivity1);

  this.Name = "Activity1";

  this.CanModifyActivities = false;

  }

  #endregion

  private SequenceActivity sequenceActivity1;

  private SequenceActivity sequenceActivity2;

  private CodeActivity codeActivity2;

  private ParallelActivity parallelActivity1;

  private CodeActivity codeActivity1;

  private SequenceActivity sequenceActivity3;

  private SequenceActivity sequenceActivity4;

  private CodeActivity codeActivity3;

  }

  }

  
  

• DavidAWinter

  Haha.

  Yep, I'm going through to make sure no soldiers were left behind.

  Thanks Jared.

  
  
  
• Using a Parallel activity in a custom Composite activity (Beta 2)