Approving workflow programaticaly

Question

I am trying to reject a workflow task programaticaly but the problem I am facing is the outcome is not being updated.below is my code

ht[SPBuiltInFieldId.PercentComplete] = 1.0f;
ht["PercentComplete"] = 1.0f;
ht["Status"] = "InProgress";
ht[SPBuiltInFieldId.TaskStatus] = SPResource.GetString(new CultureInfo((int)task.Web.Language, false), Strings.WorkflowTaskStatusComplete, new object[0]);
ht[SPBuiltInFieldId.WorkflowOutcome] = "Rejected";
ht["TaskStatus"] = "Rejected";
ht["FormData"] = SPWorkflowStatus.Completed;
ht["TaskOutcome"]="Rejected";
ht[SPBuiltInFieldId.Completed] = "TRUE";

Answer 1

I have been using below function in multiple projects and it works well.

private static bool AlterTask(SPListItem task, bool fSynchronous, string param)
{
    int attempts = 5;
    int millisecondsTimeout = 100;
    Hashtable htData = new Hashtable();
    htData[SPBuiltInFieldId.Completed] = "TRUE";
    htData["Completed"] = "TRUE";
    htData[SPBuiltInFieldId.PercentComplete] = 1.0f;
    htData["PercentComplete"] = 1.0f;
    htData["Status"] = "Completed";
    htData[SPBuiltInFieldId.TaskStatus] = SPResource.GetString
        (new CultureInfo((int)task.Web.Language, false),
        Strings.WorkflowStatusCompleted, new object[0]);
    if (param == "Approved")
    {
        htData[SPBuiltInFieldId.WorkflowOutcome] = "Approved";
        htData["TaskStatus"] = "Approved";
    }
    else
    {

        htData[SPBuiltInFieldId.WorkflowOutcome] = "Rejected";
        htData["TaskStatus"] = "Rejected";
    }

    htData["FormData"] = SPWorkflowStatus.Completed;
    if ((int)task[SPBuiltInFieldId.WorkflowVersion] != 1)
    {
        SPList parentList = task.ParentList.ParentWeb.Lists[new Guid(task[SPBuiltInFieldId.WorkflowListId].ToString())];
        SPListItem parentItem = parentList.Items.GetItemById((int)task[SPBuiltInFieldId.WorkflowItemId]);
        for (int i = 0; i < attempts; i++)
        {
            SPWorkflow workflow = parentItem.Workflows[new Guid(task[SPBuiltInFieldId.WorkflowInstanceID].ToString())];
            if (!workflow.IsLocked)
            {
                task[SPBuiltInFieldId.WorkflowVersion] = 1;
                task.SystemUpdate();
                break;
            }
            if (i != attempts - 1)
                Thread.Sleep(millisecondsTimeout);
        }
    }
    return SPWorkflowTask.AlterTask(task, htData, fSynchronous);
}

Now you can invoke this as below

//For Rejecting
bool isApproveReject = AlterTask(task, true, "Rejected");
//For Approving
bool isApproveReject = AlterTask(task, true, "Approved");