asp.net MVC5 DropDownListFor中bool?类型赋值为null的解决办法

使用ToString() 将null转换为string即可

@Html.DropDownListFor(model => model.AllowedPublished,　　new List<SelectListItem> {　　new SelectListItem() { Text = "未审核", Value = (null as bool?).ToString() },　　new SelectListItem() { Text = "已通过", Value = "true" },　　new SelectListItem() { Text = "未通过", Value = "false" }})