asp.net-mvc – SelectList选择的值未转移到DropDownList

>提交表单时绑定到所选值的标量属性
>将选项绑定到的集合

在您的示例中,您只有这两件事中的一件(第二件).您的第一个参数称为OwnerList,并且您将ViewBag.OwnerList作为第二个参数传递.

所以：

@Html.DropDownList(
    "SelectedOwnerId",new { @onchange = "this.form.submit();" }
)

显然我会建议你使用强类型视图和视图模型.显然摆脱了弱类型的ViewBag / ViewData / ViewCrap.

首先,设计一个视图模型以满足视图的要求(从目前为止显示的是显示下拉列表)：

public class OwnerViewModel
{
    [DisplayName("Choose product owner: ")]
    public string SelectedOwnerId { get; set; }

    public IEnumerable<SelectListItem> OwnerList { get; set; }
}

然后一个控制器：

public class ReportController: Controller
{
    public ActionResult ProductsByOwners()
    {
        var model = new OwnerViewModel
        {
            // preselect the second owner
            SelectedOwnerId = "2",// obviously those come from your database or something
            OwnerList = new[] 
            {
                new SelectListItem { Value = "1",Text = "owner 1" },new SelectListItem { Value = "2",Text = "owner 2" },new SelectListItem { Value = "3",Text = "owner 3" },}
        };
        return View(model);
    }

    [HttpPost]
    public ActionResult ProductsByOwners(OwnerViewModel model)
    {
        ...
    }
}

并且您有一个相应的强类型视图：

@model OwnerViewModel
@using (Html.BeginForm("ProductsByOwners",new { id = "ProductsByOwners" }))
{            
    @Html.LabelFor(x => x.SelectedOwnerId)
    @Html.DropDownListFor(
        x => x.SelectedOwnerId,Model.OwnerList,new { onchange = "this.form.submit();" }
    )
}