public class Auction
{
public string Title { get; set; }
public string category { get; set; }
}
和控制器：
[HttpGet]
public ActionResult UserForm()
{
var categoryList = new SelectList(new[] { "auto","elec","games","Home" });
ViewBag.categoryList = categoryList;
return View();
}
在视图中我有以下几行：
<div class="editor-field">
@Html.DropDownListFor(model =>
model.category,(SelectList)ViewBag.categoryList)
@Html.ValidationMessageFor(model => model.category)
</div>
我尝试保存表单时遇到的错误是：
There is no ViewData item of type ‘IEnumerable’ that
has the key ‘category’. Description: An unhandled exception occurred
during the execution of the current web request. Please review the
stack trace for more information about the error and where it
originated in the code.Exception Details: System.InvalidOperationException: There is no
ViewData item of type ‘IEnumerable’ that has the key
‘category’.
我不明白是什么问题,因为我做了(或试图做)本指南中完成的所有事情：
https://www.youtube.com/watch?v=7HM6kDBj0vE
该视频也可以在此链接中找到(第6章 – 自动绑定到请求中的数据)：
http://www.lynda.com/ASPNET-tutorials/ASPNET-MVC-4-Essential-Training/109762-2.html
解决方法
The error i get when i try to save the form
这就是你的问题所在.我怀疑你没有在post方法中重建你的列表. get方法中的以下代码行也应该在post方法中,特别是如果要返回相同的视图,或者在下拉列表中使用ViewBag.categoryList的视图.
var categoryList = new SelectList(new[] { "auto","Home" });
ViewBag.categoryList = categoryList;
当您使用带有dropdownlistfor html帮助器的null对象时,会出现这种错误.如果您执行类似的操作,则可以轻松复制该错误
@Html.DropDownListFor(model => model.PropertyName,null)
// or
@Html.DropDownList("dropdownX",null,"")
