Remove Comma when posting number to SQL Error:System.InvalidOperationException: - asp.net-mvc

Question

How can I remove a comma from the value when posting back to SQL? My SQL field is decimal but sometimes a value in the user will enter 10,000 and not 10000 so the post fails. So the strange this is I get an error message:
System.InvalidOperationException: 'The ViewData item that has the key 'TypeOf' is of type 'System.String' but must be of type 'IEnumerable'.'
Which happens with a comma is put in Amount - without a comma in amount all is fine?
Thanks,
EB
<div class="form-group">
#Html.LabelFor(model => model.TypeOf, htmlAttributes: new { #class = "required control-label col-md-2" })
<div class="col-md-10">
#Html.DropDownListFor(model => model.TypeOf, (IEnumerable<SelectListItem>)ViewBag.TypesOfLoan, null, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.TypeOf, "", new { #class = "text-danger" })
</div>
</div>
View:
#Html.(model => model.Amount, new { htmlAttributes = new { #class = "form-control", #style = "width:110px" } })
CS:
public Nullable<decimal> Amount { get; set; }
Controller:
public ActionResult CreateOrder(Order newOrder)
{
if (ModelState.IsValid)
{
db.Orders.Add(newOrder);
db.SaveChanges();
return RedirectToAction("Orders");
}
else
{
return View(newOrder);
}
}

Answer 1

If the user can add commas then it is no longer a decimal, which means your field is a text or varchar.
NOTE You can stop the user from entering the comma or any other funny character at all
#Html.TextBoxFor(model => model.Amount, new {#type="number"})
One of the things you can do is to use string replace and the parse to double
To replace the comma use
var amount = amount_input.Replace(',', '');
to parse to double use
var amount_as_double = double.Parse(amount, CultureInfo.InvariantCulture)
EDIT
looking at your question, I would not know if you are using #Html.TextBoxFor or and also no know how you are positing the form to the controller.
if your controller method looks like this
[HttpPost]
public ActionResult Index(Model model)
{
//let's say no1 is decimal, model.no1 is going to be 0 if the user enters a comma and string.Replace is not going to work
var amount = model.no1;
...
}
but of you are using something like
[HttpPost]
public ActionResult Index(FormCollection collection)
{
var amount = collection["Amount"].Replace(',', '')
...
}