How to pass data from the view to a controller - asp.net-mvc-4

Question

When I select a product from the table and click the submit button.
The ProductID and quantity from the dropdown list is passed back to the controller.
But my controller always receives the same ProductID regardless of what product I select.
Any pointer or help much appreciated.
#foreach (var t in Model.TyreFittedList)
{
<tr>
<td class="text-center">#t.ProductID</td>
<td>#t.Brand #t.Pattern <br /> #t.Full_size <br /></td>
<td>#t.Label_Roll</td>
<td>#t.Label_Wetgrip</td>
<td>#t.Label_Noise1<span>dB</span></td>
<td>
#t.ProductUnitSalePriceMailOrder.Value.ToString("C", CultureInfo.CreateSpecificCulture("en-GB"))<br />
</td>
<td>
#Html.DropDownListFor(model => model.SelectedProductId, new SelectList(Model.Quantity, "Id", "Quantity"), "0", new { style = "width: 60px;" })
<input type="hidden" name="ProductID" value="#t.ProductID" />
<input type="submit" class="btn btn-primary btn-sm btn-Order" name="Action:Order" value="Add" />
</td>
</tr>
}
[HttpPost]
public ActionResult SubmitSearchResultsMailOrder(ApplicationViewModel model, FormCollection collection, int? ProductID)
{
if (ModelState.IsValid)
{
if (Request.Form["Action:Order"] != null)
{
int qty = model.SelectedProductId;
int? productID = ProductID;
}
}
return CurrentUmbracoPage();
}