Enum.Parse不能隐式转换类型“对象”到显式转换存在（你错过了一个演员？） [英] Enum.Parse Cannot implicitly convert type 'object' to An explicit conversion exists (are you missing a cast?)

问题描述

我正在使用ASP.NET MVC 5实体框架，在我的视图中，我有一个下拉菜单，我正在尝试使用枚举来填充下拉菜单。这是我在课堂上得到的：

  public enum occupancyTimelineTypes：int 
 {
 TwelveMonths = 12 ，
 FourteenMonths = 14，
 SixteenMonths = 16，
 EighteenMonths = 18 
} 
  

，这个：

  [DisplayName（Occupancy Timeline）] 
 [必需] 
 public string occupancyTimeline {get;组; } 
 
 public occupancyTimelineTypes occupancyTimelineType 
 {
 get 
 {
 return Enum.Parse（typeof（occupancyTimelineTypes），occupancyTimeline）; 
 
} 
} 
  

我的问题是，我正在一个错误我不知道如何修复：

 不能隐式转换类型对象到显式转换存在（你错过了一个演员？）
  

我正在填充我的下拉菜单：

  @ Html.DropDownListFor（model => model.occupancyTimeline，Model.occupancyTimelineType.ToSelectList（））; 
  

这里是我的 ToSelectList（）方法public static class MyExtensions
{
public static SelectList ToSelectList（this occupancyTimelineTypes enumObj）
{
var values =从Enum.GetValues（typeof（occupancyTimeline））中的occupancyTimeline e
选择新的{Id = e，Name = string.Format（{0} Months，Convert.ToInt32（e ））};
返回新的SelectList（值，Id，Name，enumObj）;
}
}

我不能使用，不会使用 Html.EnumDropDownListFor（），因为出现太多错误，并且它是一个噩梦来实现并修复这些错误。

这必须是 @ Html.DropDownListFor

解决方案

枚举。解析返回对象（它不是通用的），所以你需要显式地转换你的返回值。使用：

  return（occupancyTimelineTypes）Enum.Parse（typeof（occupancyTimelineTypes），occupancyTimeline）; 
  

I am using ASP.NET MVC 5 Entity Framework, in My view I have a dropdown menu, what I am trying to is use enum to populate dropdown menus. This is what I got in my class:

public enum occupancyTimelineTypes : int
    {
        TwelveMonths = 12,
        FourteenMonths = 14,
        SixteenMonths = 16,
        EighteenMonths = 18
    }

and this:

[DisplayName("Occupancy Timeline")]
        [Required]
        public string occupancyTimeline { get; set; }

        public occupancyTimelineTypes occupancyTimelineType
        {
            get
            {
                return Enum.Parse(typeof(occupancyTimelineTypes), occupancyTimeline);

            }
        }

my problem is, I am getting an error I have no idea how to fix:

Cannot implicitly convert type 'object' to An explicit conversion exists (are you missing a cast?)

I am populating my dropdown menu like so:

@Html.DropDownListFor(model => model.occupancyTimeline,Model.occupancyTimelineType.ToSelectList());

and here is my ToSelectList() Method

public static class MyExtensions
    {
        public static SelectList ToSelectList(this occupancyTimelineTypes enumObj)
        {
            var values = from occupancyTimeline e in Enum.GetValues(typeof(occupancyTimeline))
                         select new { Id = e, Name = string.Format("{0} Months", Convert.ToInt32(e)) };
            return new SelectList(values, "Id", "Name", enumObj);
        }
    }

I CANNOT AND WILL NOT USE Html.EnumDropDownListFor() as too many errors appear and its a nightmare to put in place and fix these errors.

This has to be @Html.DropDownListFor

解决方案

Enum.Parse returns object (it is not generic) so you need to explicitly cast your return value. Use:

return (occupancyTimelineTypes)Enum.Parse(typeof(occupancyTimelineTypes), occupancyTimeline);

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