Getting error for @html.dropdownlistfor on post - "The ViewData item that has the key 'product' is of type 'System.Int32' but must be of type 'IEnumerable'."}

The ViewModel is:
namespace MockBDPWorkflowTestApp.ViewModels {
public class WorkFlowTestViewModel { public string processInstance { get; set; } public string mail { get; set; } public string selectedProd { get; set; } public int product { get; set; } public List<SelectListItem> products { get; set; } } }
The controller is : public class WorkFlowTestController : Controller { // // GET: /WorkFlowTest/
public ActionResult OpenSubmission(string processId, string mailId, ViewModels.WorkFlowTestViewModel SubmissionModelView) {
SubmissionModelView.processInstance = processId; SubmissionModelView.mail = mailId; SubmissionModelView.products = new List<SelectListItem>() { new SelectListItem{ Text = "GL", Value = "1" } , new SelectListItem { Text = "Property", Value = "2", Selected = true }, new SelectListItem { Text = & ...