Get related item of a task

Question

I am starting workflow for a list item.

Workflow creats tasks.

How can i get a related item (list item) of a task programmaticaly?

SPBuiltInFieldId.WorkflowListId does no work.

Answer 1

Assuming your workflow is an out-of-the-box Approval workflow or a workflow that has been created using the 2010 platform (containing the "Start Approval Process" action), then you need to use the Workflow Item ID field (internal name is WorkflowItemId).

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If your tasks are created by a workflow using the 2013 platform containing the "Assign a task" or the "Start a task process" actions, then you want to use the Related Items field (internal name is RelatedItems).

This field contains a JSON string that looks like this: [{"ItemId":2,"WebId":"c4762c49-735d-4672-ba09-9b58c08829ea","ListId":"f1b87a67-4415-4882-903c-fb2bc3caf002"}]. As you can see the JSON string is an array containg an object with a property called ItemId which is the id of the item that your workflow ran on to create the task.

Answer 2

Thanks to Mihail.

After week of hard work my code solution is (for Sharepoint 2013).

namespace ER1.EventReceiver6
{
    /// <summary>
    /// List Item Events
    /// </summary>
    public class EventReceiver6 : SPItemEventReceiver
    {
        /// <summary>
        /// An item was updated.
        /// </summary>
        public override void ItemUpdated(SPItemEventProperties properties)
        {
            base.ItemUpdated(properties);       
            if (properties.ListTitle == "Tasks")
            {
            SPList Listcurrent = properties.Web.Lists["Tasks"];
            SPListItem taskid = Listcurrent.GetItemById(properties.ListItemId);
                bool flag = Convert.ToBoolean(taskid["updated"]);// we need "updated" to stop infinity loop
                    if (flag == false) // Already updated? No actions
                {          
                string jsonString = properties.ListItem[SPBuiltInFieldId.RelatedItems].ToString();

           int position2 = 0;   

           position2 = jsonString.IndexOf("WebId");    

            string IDSTRING= jsonString.Substring(11, position2 - 13);// bad way, but quick.


            SPList parent = properties.Web.Lists["Questions"];


                SPListItem parentItem = parent.GetItemById(Convert.ToInt32(IDSTRING));

                taskid["_x041d__x0430__x0437__x0432__x04"] = parentItem["Title"];
                taskid["_x0414__x043e__x043a__x043b__x04"] = parentItem["AssignedTo"];
                taskid["_x041f__x0440__x0438__x0433__x04"] = parentItem["_x041f__x0440__x0438__x0433__x04"];
                taskid["_x0421__x043e__x0433__x043b__x04"] = parentItem["_x0421__x043e__x0433__x043b__x04"];
                taskid["_x041f__x0440__x043e__x0435__x04"] = parentItem["Body"].ToString();

                taskid["updated"] = 1;// flag for check
                CopyItem(parentItem,taskid);
                try

                {
                    taskid.Update();               
                }
                catch (Exception ex)
                {
                    Debug.WriteLine("Exception Message: " + ex.Message);
                }
            }
            }
        }

        public void CopyItem(SPListItem srcItem, SPListItem destItem)
        {
            foreach (string attachmentName in srcItem.Attachments)
            {
                SPFile file = srcItem.ParentList.ParentWeb.GetFile(srcItem.Attachments.UrlPrefix + attachmentName);
                byte[] data = file.OpenBinary();
                destItem.Attachments.Add(attachmentName, data);
            }

        }
    }
}