CheckBoxList for Enum types MVC Razor

问题

In my c#.net MVC application i would like to display checkbox list for Enum types.

I have an enum type

[Flags]
public enum ModeType
{
Undefined = 0,
Read= 1,
Edit= 2
  }

and my Model is

Public TrainingModel
   {
         public int UserID {get;set;}
         public ModeType Type {get;set}
   }

In my view i need two checkbox one for Read and the other for Edit So i tried

    @Html.CheckBoxFor(m => m.Type== ModeType.Read)
@Html.CheckBoxFor(m => m.Type== ModeType.Edit)

But this give me error "Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions."

I worked around this problem by adding two more properties to my model

 Public TrainingModel
   {
         public int UserID {get;set;}
         public ModeType Type {get;set}
         public bool IsRead
         {
           get{Type.HasFlag(ModeType.Read);}
           set{Type |=ModeType.Read;}
         }
         public bool IsEdit
         {
           get{Type.HasFlag(ModeType.Edit);}
           set{Type |=ModeType.Edit;}
         }

   }

and then making my view

@Html.CheckboxFor(m => m.IsRead)
@Html.CheckboxFor(m => m.IsEdit)

I know that the way i have approached it is not correct and there should be a better way to achieve this. Could someone please advise me on this.

回答1:

Here is how I tackled this to transforms Enums into Select Lists. Enum.cshtml (an Editor Template, with a UI Hint to point to it):

@model Enum
@Html.DropDownListFor(model => model, Model.ToSelectList(), "Select")

Then the Extension method used in the view:

    /// <summary>
    /// Gets a select list from an enum.
    /// </summary>
    /// <param name="enumObject">The enum object.</param>
    /// <returns></returns>
    public static SelectList ToSelectList(this Enum enumObject)
    {
        List<KeyValuePair<string, string>> selectListItemList = null;
        SelectList selectList = null;

        try
        {
            // Cast the enum values to strings then linq them into a key value pair we can use for the select list.
            selectListItemList = Enum.GetNames(enumObject.GetType()).Cast<string>().Select(item => { return new KeyValuePair<string, string>(item, item.PascalCaseToReadableString()); }).ToList();

            // Remove default value of Enum. This is handled in the editor template with the optionLabel argument.
            selectListItemList.Remove(new KeyValuePair<string, string>("None", "None"));

            // Build the select list from it.
            selectList = new SelectList(selectListItemList, "key", "value", enumObject);

        }
        catch (Exception exception)
        {
            Functions.LogError(exception);
        }

        return selectList;
    }

To refactor this solution into Check Box Lists, you could simply pass back the Key Value Pairs from the function and loop through them in the editor template.

I hope this is of some help.

来源：https://stackoverflow.com/questions/18087615/checkboxlist-for-enum-types-mvc-razor

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