Shorthand is used to decide which option is selected on pageload of razor Html.DropDownListFor(). You can try to run the following code snippet −
// return Boolean value
@Html.DropDownListFor(m => m.Valeur,
new List< SelectListItem > { //new list item list item1 is generated
new SelectListItem { Value = "0" , Text = "Show", Selected = Model.Valeur == 0 },
new SelectListItem { Value = "1" , Text = "Hide", Selected = Model.Valeur != 0 },
}, new { @class = “selectnew" })