ASP.NET MVC：DropDownList 验证
注意：以下只是一个示例。
我对 ASP.NET MVC 还很陌生，我正在尝试了解下拉列表验证的工作原理。我的 ProfileViewModel 类中有以下属性：
[DisplayName("Gender")]
public bool? Gender { get; set; }
null 表示“未知”，true 女性，false > 男性。在视图模型构造函数中
AllGenders = new List<SelectListItem>(2)
{
new SelectListItem {Text = "Unknown", Value = "null"},
new SelectListItem {Text = "Male", Value = "false"},
new SelectListItem {Text = "Female", Value = "true"}
};
，我首先似乎在填充 List 时必须使用字符串，这感觉有点奇怪。真的是这样的吗？
其次，当我在列表中选择“未知”时，验证失败，告诉我：
值“null”对于性别无效。
这是为什么？当我删除“null”选项并将 Gender 更改为简单的 bool 时，一切看起来都很好。
这是 ASPX：（
<%= Html.DropDownList("Gender", Model.AllGenders) %>
我无法让 DropDownListFor 正常工作，似乎许多其他人也有同样的问题。）
任何帮助表示赞赏！
Note: The following is just an example.
I'm pretty new to ASP.NET MVC and I'm trying to get my head around how validation of dropdown lists work. I have the following property in my ProfileViewModel class:
[DisplayName("Gender")]
public bool? Gender { get; set; }
null is meant to mean "unknown", true female and false male. In the view model constructor I
AllGenders = new List<SelectListItem>(2)
{
new SelectListItem {Text = "Unknown", Value = "null"},
new SelectListItem {Text = "Male", Value = "false"},
new SelectListItem {Text = "Female", Value = "true"}
};
First of all, it seems that I have to use strings when populating a List<SelectListItem>, which feels kinda weird. Is this really how it's done?
Secondly, when I choose "Unknown" in the list the validation fails telling me:
The value 'null' is not valid for Gender.
Why is that? When I remove the "null" option and change Gender to a simple bool, everything seems fine.
This is the ASPX:
<%= Html.DropDownList("Gender", Model.AllGenders) %>
(I can't get DropDownListFor to work correctly and it seems that many others have the same problem.)
Any help appreciated!
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