WWF in asp.net and beta 2.2

WWF in asp.net and beta 2.2

• gnick

  Can you just add it during the application startup (i,e on Application_Start of your Global.asax)
  
  
  

• appler

  ok i add it to the application startup and it work but i have another question

  now the workflow hosted under the asp.net process this mean if the server down my workflow 's down and if i have sechdule tasks it's not gone executed coz the server is down what do u think about this

  Thanks,

  Tamer

  
  

• SkotChadwick

  Andres,

  Here is how I am doing currently in my project. I ran across the same problem last week and Paul Andrew and Mark Schmidt were very helpful to me, so let me attempt to return the favor.

  In my global.asax I have

  ---------------------------------------------------------------------------------------------

  <%@ Import Namespace="System.Workflow.Runtime"%>

  Public Shared workflowRuntime As WorkflowRuntime = New WorkflowRuntime()

  Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)

  workflowRuntime.StartRuntime()

  End Sub

  ----------------------------------------------------------------------------------------------------------------------

  In the page that runs the workflow I have

  ----------------------------------------------------------------------------------------------

  Imports System

  Imports System.Data

  Imports System.Collections.Generic

  Imports System.Globalization

  Imports System.Threading

  Imports System.Workflow.Runtime

  Imports System.Workflow.Runtime.Hosting

  Partial Class ReferredBySearch

  Inherits System.Web.UI.Page

  'A workflow is always run asychronously; the main thread waits on this event so the program

  ' doesn't exit before the workflow completes

  Shared WaitHandle As New AutoResetEvent(False)

  Public dt As DataTable

  Private Sub StartWorkflow()

  ' Set up the parameters

  Dim parameters As Dictionary(Of String, Object) = New Dictionary(Of String, Object)()

  parameters.Add("FirstName", txtFirstName.Text)

  parameters.Add("LastName", txtLastName.Text)

  'NOTE: This requires the configuration section to be named "WorkflowRuntime".

  Dim workflowRuntime As WorkflowRuntime = Global.ASP.global_asax.workflowRuntime

  If Not workflowRuntime.IsStarted Then

  workflowRuntime.StartRuntime()

  End If

  AddHandler workflowRuntime.WorkflowCompleted, AddressOf OnWorkflowCompleted

  AddHandler workflowRuntime.WorkflowTerminated, AddressOf OnWorkflowTerminated

  'Workflow.findReferrer is the name of the project/workflow

  Dim workflowInstance As WorkflowInstance = workflowRuntime.CreateWorkflow(GetType(Workflow.findReferrer), parameters, Guid.NewGuid)

  workflowInstance.Start()

  WaitHandle.WaitOne()

  workflowRuntime.StopRuntime()

  End Sub

  Protected Sub btnNameSearch_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnNameSearch.Click

  StartWorkflow()

  End Sub

  Public Sub OnWorkflowCompleted(ByVal sender As Object, ByVal e As WorkflowCompletedEventArgs)

  Dim t As DataTable = CType(e.OutputParameters("dtReferrer"), DataTable)

  GridView1.DataSource = t

  GridView1.DataBind()

  WaitHandle.Set()

  End Sub

  Public Sub OnWorkflowTerminated(ByVal sender As Object, ByVal e As WorkflowTerminatedEventArgs)

  Response.Write(e.Exception.Message) 'Just for now until I expand this

  WaitHandle.Set()

  End Sub

  End Class

  ---------------------------------------------------------------------------------------------------------------------------

  My web.config looks like this

  ---------------------------------------------------------------------------------------------------------------------------

  <configSections>

  <section name="WorkflowRuntime" type="System.Workflow.Runtime.Configuration.WorkflowRuntimeSection, System.Workflow.Runtime, Version=3.0.00000.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

  </configSections>

  <WorkflowRuntime Name="WorkflowServiceContainer">

  <Services>

  <add type="System.Workflow.Runtime.Hosting.ASPNetThreadingService, System.Workflow.Runtime, Version=3.0.00000.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

  </Services>

  </WorkflowRuntime>

  <assemblies>

  <add assembly="System.Workflow.Activities, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

  <add assembly="System.Workflow.ComponentModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

  <add assembly="System.Workflow.Runtime, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

  </assemblies>

  <httpModules>

  <add name="WorkflowHost" type="System.Workflow.Runtime.Hosting.WorkflowWebHostingModule, System.Workflow.Runtime, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

  </httpModules>

  ---------------------------------------------------------------------------------------------------------------------------

  The workflow I created runs and returns a datatable back to the web page. This is what I have and it works with beta 2.2

  If anyone has any pointers I would also greatly appreciate it, as I am new to WWF but really think that it will change the way in which we write apps, BIG TIME!!!

  -John

  
  

• Kieme Ile

  I agree. But do not have a solution. Can anyone suggest a pattern to address this

  -John

  
  

• Vaidotas

  John your post's so useful and help me alot but i have a few questions what about

  ExternalDataExchangeService should i add it to the global too as static member actually i moved it to the global but still have problems

  ExternalDataExchangeService dataService;

  dataService = ASP.global_asax.dataService;

  messageService = new MyWorkFlow.MessageService();

  dataService.AddService(messageService);

  it work fine for first time but on the second one i get this error

  An instance of ExternalDataExchangeService of type Escalation.IMessageService already exists in the runtime container

  this errors is drive me crazy i'm doing gr8 with windows app but now with asp.net i can't do it oh my god

  hope you can help

  Thanks in advanced

  
  

• MStrange

  Well, I think (but I might be wrong on this) that there is currently no way to host WF that will get you that kind of availability, so be prepared to write a lot of code and test a lot to create your own hosting that can provide at least a fraction of that. Painful, but I think it is close to reality right now.
  
  The first thing to recognize here, is that you'll need a more reliably hosting mode to work with this. Personally my opinion is: while hosting WF in ASP.NET can be seen as useful (and possibly simpler for some scenarios), this is only an acceptable for short-lived workflows such as page flows (modeling page interactions). ASP.NET most certainly is *not*, to me, an acceptable hosting environment for long-running workflows.
  
  Now, I'll be honest and tell you that I don't know what an alternative hosting model might be. Most likely, we won't have that kind of robust hosting environment until BizTalk 200X (with X>6) ships with WF facilities (and I don't know how much change we'll need to see in WF itself for this to be a reality), but you might get at least something better using some form of clustering meanwhile. Perhaps you can host your ASP.NET app in a windows cluster. I would consider hosting my long-running workflows inside a Windows Service instead, and take advantage of the SCM facilities for automatic restarting of failed services, and possibly look into clustering the service in an active/passive fashion. This does bring a few problems with it, of course, and will take quite a bit more work (particularly communicating the workflows in your custom host with the external applications that access it).
  
  Anyone has any other thoughts on this
  
  
  
• WWF in asp.net and beta 2.2