DropDownList对于列表中的第一个选择不显示/保留 Null
我通过 SharpArch 有一个 MVC 应用程序。我认为：
Html.DropDownListFor(x => x.Location,
new SelectList(Model.PossibleLocations, "Id", "Address"),
"-- No Location --")
我有两个问题。
- 当视图绑定到模型时，下拉列表不会更新。
- 除非我尝试顶部的“无位置”，否则选择会正确保留。
我能够通过将 x.Location 更改为 x.Location.Id 来解决第一点，但随后我遇到了其他问题。
我可以找到很多 DropDownList 的示例，但没有显示保存 null 的示例。
任何帮助表示赞赏。
谢谢
更新：
我刚刚升级了 Resharper（一个小更新），并收到提示填写它 DropDownListFor。为什么这会有所不同？它本来足以绑定，但现在根本不起作用。
I have an MVC app via SharpArch. In the view I have:
Html.DropDownListFor(x => x.Location,
new SelectList(Model.PossibleLocations, "Id", "Address"),
"-- No Location --")
I have 2 issues.
- The Dropdown is not getting updated when the view gets bound to the model.
- A selection gets persisted correctly except when I try the top "no location".
I was able to take care of the first point by changing x.Location to x.Location.Id but then I had other issues.
I can find plenty of examples for DropDownList, but none in which saving a null is shown.
Any help is appreciated.
Thanks
UPDATE:
I just upgraded Resharper (a minor update) and am getting prompted to fill it DropDownListFor. Why would that make a difference? It was working enough to bind and now it doesn't work at all.
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在传递给
View之前，您始终可以将“空”SelectListItem插入到PossibleLocations集合中，并检查该“空”值（0 表示例如）当表单发布时You could always insert the "empty"
SelectListIteminto yourPossibleLocationscollection before passing to theViewand check for that "empty" value (0 for instance) when the form is posted尝试“展平”您的模型类，以便 LocationId 是您要绑定的实际值（即向您的模型添加“LocationId”属性，并为
x => x.LocationId创建一个 DropDownList ）。Try "flattening" your model class so that LocationId is the actual value you're binding to (i.e. add a "LocationId" property to your model, and create a DropDownList for
x => x.LocationId).