Code snippet to create a Tasks list and associate it with a Parallel Approval workflow in a Pages library

The requirement to write this code was, After export/import, workflow modification for approvers was failing. Approvers were not able to perform the Approval workflow operations and then we tested that if we create a new Tasks list and modify the existing Approval workflow association then everything starts working so we needed a code which can do this operation for whole site collection.

Following code snippet will create a Tasks list with name “MS Tasks” and associate it with a Parallel Approval workflow in a “Pages” library in root site as well as in all the sub sites.

    1:  using System;

    2:  using System.Collections.Generic;

    3:  using System.ComponentModel;

    4:  using System.Data;

    5:  using System.Drawing;

    6:  using System.Linq;

    7:  using System.Text;

    8:  using System.Windows.Forms;

    9:  using Microsoft.SharePoint;

   10:  using Microsoft.SharePoint.Publishing;

   11:  using Microsoft.SharePoint.Workflow;

   12:   

   13:  namespace WorkflowAssoc

   14:  {

   15:      public partial class Form1 : Form

   16:      {

   17:          public Form1()

   18:          {

   19:              InitializeComponent();

   20:          }

   21:   

   22:   

   23:          private void button1_Click(object sender, EventArgs e)

   24:          {

   25:              using (SPSite site = new SPSite(textBox1.Text.Trim()))

   26:              {

   27:                  using (SPWeb web = site.OpenWeb())

   28:                  {

   29:                      //executing for root site

   30:                      WorkflowModification(web);

   31:   

   32:                      //executing for all subsites

   33:                      foreach (SPWeb subweb in web.Webs)

   34:                      {

   35:                          WorkflowModification(subweb);

   36:                      }

   37:                  }

   38:              }

   39:   

   40:              MessageBox.Show("Done!");

   41:          }

   42:   

   43:          private void WorkflowModification(SPWeb web)

   44:          {

   45:              bool checkTasks = true;

   46:              bool checkPages = true;

   47:              SPList pages;

   48:              SPWorkflowAssociation WFCol;

   49:              SPList tasks;

   50:   

   51:              //making sure Pages list is available.

   52:              foreach (SPList list in web.Lists)

   53:              {

   54:                  if (list.Title == "Pages")

   55:                  {

   56:                      checkPages = false;

   57:                  }

   58:              }

   59:   

   60:              //making sure Tasks list is not available.

   61:              foreach (SPList list in web.Lists)

   62:              {

   63:                  if (list.Title == "MS Tasks")

   64:                  {

   65:                      checkTasks = false;

   66:                  }

   67:              }

   68:   

   69:              //execute only if Tasks list not available and Pages list is available

   70:              if (checkTasks && !checkPages)

   71:              {

   72:                  //creating a Tasks list

   73:                  web.Lists.Add("MS Tasks", "MS Tasks List", SPListTemplateType.Tasks);

   74:   

   75:                  //getting an object of Pages list

   76:                  pages = web.Lists["Pages"];

   77:   

   78:                  //getting an object of Tasks list and setting it in workflow association

   79:                  tasks = web.Lists["MS Tasks"];

   80:   

   81:                  //getting an object of "Parallel Approval" workflow

   82:                  //this is the only workflow available so first index

   83:                  for (int i = 0; i < pages.WorkflowAssociations.Count; i++)

   84:                  {

   85:                      WFCol = pages.WorkflowAssociations[i];

   86:   

   87:                      //setting up Tasks list 

   88:                      WFCol.SetTaskList(tasks);

   89:                      WFCol.TaskListTitle = "MS Tasks";

   90:   

   91:                      //updating the workflow association

   92:                      pages.UpdateWorkflowAssociation(WFCol);

   93:   

   94:                      //clearing the objects

   95:                      WFCol = null;

   96:                  }

   97:                  tasks = null;

   98:                  pages = null;

   99:              }

  100:          }

  101:      }

  102:  }

:: Please note that I would have just uploaded my initial code and you might want to consider proper optimization of the code and disposal of objects properly. I might not have updated the latest code here.