MVC 3控制器语法错误我的选择列表中的循环

问题描述：

我的语法创建一个月内选择列表在我的控制器内的一个月内有一些麻烦。我得到了几个月和几年的工作，但for循环造成了一些麻烦。MVC 3控制器语法错误我的选择列表中的循环

visual studio给我的错误是：“无效的初始化成员声明符”和“名称Days在当前上下文中不存在”。

视图模型

public class DateSearchViewModel 
{ 
    public int SelectedMonth { get; set; } 
    public IEnumerable<SelectListItem> Months { get; set; } 
    public int SelectedDay { get; set; } 
    public IEnumerable<SelectListItem> Days { get; set; } 
    public int SelectedYear { get; set; } 
    public IEnumerable<SelectListItem> Years { get; set; } 
}

控制器

[ChildActionOnly] 
    public ActionResult _Header() 
    { 
     var DateVM = new DateSearchViewModel 
     { 
      //Set selected value of month. 
      SelectedMonth = 5, 
      Months = new List<SelectListItem> 
      { 
       new SelectListItem {Text = "Jan", Value = "1"}, 
       new SelectListItem {Text = "Feb", Value = "2"}, 
       new SelectListItem {Text = "Mar", Value = "3"}, 
       new SelectListItem {Text = "Apr", Value = "4"}, 
       new SelectListItem {Text = "May", Value = "5"}, 
       new SelectListItem {Text = "Jun", Value = "6"}, 
       new SelectListItem {Text = "Jul", Value = "7"}, 
       new SelectListItem {Text = "Aug", Value = "8"}, 
       new SelectListItem {Text = "Sep", Value = "9"}, 
       new SelectListItem {Text = "Oct", Value = "10"}, 
       new SelectListItem {Text = "Nov", Value = "11"}, 
       new SelectListItem {Text = "Dec", Value = "12"}, 
      }, 

      //Set selected value of Day. 
      SelectedDay = 13, 
      Days = new List<SelectListItem> 
      { 
       for (var i = 1; i <= 31; i++) 
       { 
        Days.Add(new SelectListItem { Text = i.ToString(), Value = i.ToString()}); 
       } 
      }, 

      //Set selected value of Year. 
      SelectedYear = 2010, 
      Years = new List<SelectListItem> 
      { 
       new SelectListItem {Text = "2009", Value = "2009"}, 
       new SelectListItem {Text = "2010", Value = "2010"}, 
       new SelectListItem {Text = "2011", Value = "2011"}, 
       new SelectListItem {Text = "2012", Value = "2012"}, 
      } 
     }; 

     return PartialView(DateVM); 
    }

视图模型：

@Html.DropDownListFor(x => x.SelectedMonth, Model.Months)/@Html.DropDownListFor(x => x.SelectedDay, Model.Days)/@Html.DropDownListFor(x => x.SelectedYear, Model.Years)

答

你不能把一个循环，一个初始化：

Days = new List<SelectListItem> 
{ 
    for (var i = 1; i <= 31; i++) 
    { 
     Days.Add(new SelectListItem { Text = i.ToString(), Value = i.ToString()}); 
    } 
},

因此，而不是只是实例并在以后使用的循环：

var DateVM = new DateSearchViewModel 
{ 
    ... 
    Days = new List<SelectListItem>(), 
    ... 
} 

for (var i = 1; i <= 31; i++) 
{ 
    DateVM.Days.Add(new SelectListItem { Text = i.ToString(), Value = i.ToString()}); 
}

答

当编译器是想告诉你，你不能这样做。
初始值设定项只能包含表达式。

相反，你可以使用LINQ：

Days = Enumerable.Range(1, 31) 
       .Select(i => new SelectListItem { Text = i.ToString() }))

MVC 3控制器语法错误我的选择列表中的循环

相关推荐