@ this.Html.DropDownList（）没有为我选择默认值

Question

@this.Model.ActiveApplicationId
@this.Html.DropDownList("applications", new SelectList(this.Model.AllApplications, "ApplicationId", "Title", this.Model.ActiveApplicationId))

renders...

17
<select id="applications">
    <option value="16">app 16</option>
    <option value="17">app 17</option>
</select

There is no selected="selected" attr on the 2nd option, and there should be. So, by default, since none of them are selected, the 1st one is selected.

What am I missing? Thanks!

Answer 1

Why not use the strongly typed version? MVC does not respect the Selected value parameter of the SelectList.

@Html.DropDownListFor(m => m, 
    new SelectList(Model.AllApplications, "ApplicationId", "Title"))

Answer 2

DropDown Helper的第二个参数采用SelectListItem的IEnumerable类型的对象，但是您传递了SelectList类型的对象。