DropDownListFor从模型默认选择项

本文介绍了DropDownListFor从模型默认选择项的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我必须绑定到一个模型成员，以及可选择的项目列表的DropDownListFor。结合此成员的作品，但我似乎无法弄清楚是如何显示模型的当前值在页面加载时。

I have a DropDownListFor bound to a model member as well as a list of items to choose from. The binding to this member works, but what I can't seem to figure out is how to display the current value of the model when the page loads.

查看

@Html.DropDownListFor(model => model.MethodofPayment, (List<SelectListItem>)ViewBag.statuses)

控制

List<SelectListItem> statuses = new List<SelectListItem>(); statuses.Add(new SelectListItem { Text = "Approved", Value = "Approved" }); statuses.Add(new SelectListItem { Text = "Declined", Value = "Declined" }); statuses.Add(new SelectListItem { Text = "Pending", Value = "Pending" }); ViewBag.ClaimStatus = statuses;

添加optionLabel参数不工作，并返回一个空值，并在SelectListItem传递作为optionLabel参数也不行。

Adding the optionLabel argument doesn't work and returns a null value, and passing in a SelectListItem as the optionLabel parameter doesn't work either.

@Html.DropDownListFor(model => model.MethodofPayment, (List<SelectListItem>)ViewBag.methodofpayment, model.MethodOfPayment)

我希望页面显示提交相同的值，如果他们不改变列表项。

I want the page to submit the same value shown if they don't change the list item.

编辑：感谢你们，一定是一个名称冲突。我搞砸了问我的问题有点，因为我有两个下拉列表，我必须抄错了。

Thanks you guys it must have been a name conflict. I messed up asking my question a bit cause I have two drop down lists and I must have copied the wrong one.

更改的code：控制器：

The Changed Code: Controller:

List<SelectListItem> statuses = new List<SelectListItem>(); statuses.Add(new SelectListItem { Text = "Approved", Value = "Approved" }); statuses.Add(new SelectListItem { Text = "Declined", Value = "Declined" }); statuses.Add(new SelectListItem { Text = "Pending", Value = "Pending" }); ViewBag.ClaimStatuses = statuses;

查看：

@Html.DropDownListFor(model => model.ClaimStatus, (List<SelectListItem>)ViewBag.ClaimStatuses)

它制造复数，它的作品。

Made it plural and it works.

推荐答案

有时，它可能发生，你可能已经为不同的控件/变量使用相同的名称，它可能互相冲突。

Sometimes it may happen that you might have used the same name for different controls/variables and it might conflict with each other.

在你情况下，模型属性名在冲突 MethodofPayment 和你ViewBag名称 methodofpayment 结果我猜。

In you case the Model property name MethodofPayment and your ViewBag name methodofpayment results in conflict I guess.

试着改变你的ViewBag名字像 ViewBag.paymentmode 和尝试。

Try changing your ViewBag name to something like ViewBag.paymentmode and try it.

@Html.DropDownListFor(model => model.MethodofPayment, (List<SelectListItem>)ViewBag.paymentmode)