How we bind groupwise dropdownlist in MVC

See more:

MVC4

MVC5

entity-framework

I want to bind dynamic dropdownlist items group wise in MVC. My dropdown is simply bind with all list item but I want to achieve dropdownlist similar as "optgroup" html select option. Any one can help me

What I have tried:

This is my html page :
<pre>@Html.DropDownList("cProductionLines", ViewBag.cProductionLines as SelectList,  @Resources.TitleResource.ProductionLines, new { @class = "form-control", @id = "cProductionLines" })

and this is my controller code:

private void bindRequestProductionLines()
        {
            List<COP_ProductList> ProductList = OUnitOfWork.ProductListRepositories.FindBy(x => x.IsActive == true).ToList();
            var ProductionLinesList = ProductList.Select(x => new

            {
                Id = x.Id,
                Type = !CorporateSite.Helpers.CultureHelper.IsLanguageArabic ? x.Title_En : x.Title_Ar,
                Category = !CorporateSite.Helpers.CultureHelper.IsLanguageArabic ? x.COP_ProductionLines.Name_EN : x.COP_ProductionLines.Name_AR,
                CategoryId = x.COP_ProductionLines_Id
            }).ToList();

            ViewBag.cProductionLines = new SelectList(ProductionLinesList, "Id", "Type", "Category");
            
        }