public ActionResult Login(string returnUrl, UserRole? role)
public ActionResult Login(string returnUrl, UserRole? role),
public enum UserRole : short
{
/// <summary>
/// Represents a role of a registered user.
/// </summary>
Member = 1,
/// <summary>
/// Represents a role of a member that have been promoted by an admin or moderator.
/// </summary>
TrustedMember = 2,
/// <summary>
/// Forum moderator
/// </summary>
Moderator = 3,
/// <summary>
/// Admin role
/// </summary>
Admin = 10
}
请问“？”是什么意思，能详细说明吗？ enum ？??
[解决办法]
值类型不能是null，带个？就可以给它赋null值了
[解决办法]
google可空值类型
[解决办法]
可空类型，对应MVC来说，用作可选的参数。
[解决办法]
int x=0;
int? y=null;
int z=null;//报错
