Error using SPContext.Current.Web.AllUsers in Visual Studio workflow

Question

I have the following code running in a Visual Studio workflow. I am trying to specify the user who is adding list items in the code because I guess the system account (default for VS) will not allow declarative workflows to start. The declarative WF's are not started from this code but from "item updated" on the list. The WF errors out in SP with the following error:

Error in workflow! Object reference not set to an instance of an object.

        SPUser user = SPContext.Current.Web.AllUsers["wgl\\username"];
        SPUserToken token = user.UserToken;
        using (SPSite site = new SPSite(workflowProperties.SiteId, token))
        {
            using (SPWeb web = site.OpenWeb(workflowProperties.WebId))
            {
                SPList list = web.Lists["Approvals"];
                SPListItem item = list.Items.Add();
                item["Title"] = "ECO Approval";
                item["Approval Type"] = approvalType;
                item["Approver"] = workflowProperties.Item[approverColumn];
                item["ECO ID"] = workflowProperties.Item["ID"];
                item["ECO Number"] = web.Url + "/Lists/ECO/DispForm.aspx?ID=" + workflowProperties.ItemId + ", " + workflowProperties.ItemId;
                item.Update();
                SPWorkflowManager objWorkflowManager = null;
                SPWorkflowAssociationCollection objWorkflowAssociationCollection = null;
                objWorkflowManager = item.Web.Site.WorkflowManager;
                objWorkflowAssociationCollection = item.ParentList.WorkflowAssociations;
                foreach (SPWorkflowAssociation objWorkflowAssociation in objWorkflowAssociationCollection)
                {
                    SPWorkflow.CreateHistoryEvent(this.workflowProperties.List.ParentWeb, workflowId, 0, workflowProperties.OriginatorUser, TimeSpan.MinValue, "WorkFlow " + objWorkflowAssociation.Name, "WorkFlow " + objWorkflowAssociation.Name, "WorkFlow " + objWorkflowAssociation.Name);
                    if (objWorkflowAssociation.Name == "Approval Workflow")
                    {
                        site.WorkflowManager.StartWorkflow(item, objWorkflowAssociation, objWorkflowAssociation.AssociationData);
                    }
                }
            }
        }

The only thing that was changed was adding:

        SPUser user = SPContext.Current.Web.AllUsers["wgl\\switter"];
        SPUserToken token = user.UserToken;
        using (SPSite site = new SPSite(workflowProperties.SiteId, token))

Answer 1

Workflows do not have an SPContext so SPContext.Current will always be null. In order to do what you appear to be trying to do, you may have to open the site once as the AppPool account to get the user token then release the site. Then open it again using the token like you are doing now. Something like this :

SPUserToken token = null;
using (SPSite site = new SPSite(workflowProperties.SiteId))
{
   token = site.RootWeb.GetUserToken("wgl\\username");
}

using (SPSite site = new SPSite(workflowProperties.SiteId, token))
{
   ... other code ...
}

Answer 2

I nailed it thanks in large part to Dave! here is what I did:

    public void addApproval(string approvalType, string approverColumn)
    {
        SPSecurity.RunWithElevatedPrivileges(delegate()
        {
            //get the site owner token
            SPUser user = null;
            using (SPSite site1 = new SPSite(workflowProperties.SiteId))
            {
                user = site1.Owner;
            }
            SPUserToken token = user.UserToken;

            using (SPSite site = new SPSite(workflowProperties.SiteId, token))
            {
                using (SPWeb web = site.OpenWeb(workflowProperties.WebId))
                {
                    SPList list = web.Lists["Approvals"];
                    SPListItem item = list.Items.Add();
                    item["Title"] = "ECO Approval";
                    item["Approval Type"] = approvalType;
                    item["Approver"] = workflowProperties.Item[approverColumn];
                    item["ECO ID"] = workflowProperties.Item["ID"];
                    item["ECO Number"] = web.Url + "/Lists/ECO/DispForm.aspx?ID=" + workflowProperties.ItemId + ", " + workflowProperties.ItemId;
                    item.Update();
                    SPWorkflowManager objWorkflowManager = null;
                    SPWorkflowAssociationCollection objWorkflowAssociationCollection = null;
                    objWorkflowManager = item.Web.Site.WorkflowManager;
                    objWorkflowAssociationCollection = item.ParentList.WorkflowAssociations;
                    foreach (SPWorkflowAssociation objWorkflowAssociation in objWorkflowAssociationCollection)
                    {
                        SPWorkflow.CreateHistoryEvent(this.workflowProperties.List.ParentWeb, workflowId, 0, workflowProperties.OriginatorUser, TimeSpan.MinValue, "WorkFlow " + objWorkflowAssociation.Name, "WorkFlow " + objWorkflowAssociation.Name, "WorkFlow " + objWorkflowAssociation.Name);
                        if (objWorkflowAssociation.Name == "Approval Workflow")
                        {
                            site.WorkflowManager.StartWorkflow(item, objWorkflowAssociation, objWorkflowAssociation.AssociationData);
                        }
                    }
                }
            }
        });
    }

The list item now shows up as being created and modified by a user (owner) instead of the system account.