c# - 从 GetEnumSelectList<> 获取文本值而不是索引值

Question

GetEnumSelectList<> 返回索引值而不是文本值。如何获取文本值？

Usage: 
<select asp-for="Policy" asp-items="Html.GetEnumSelectList(typeof(PolicyEnum))" class="form-control"></select>

Results:
<select class="form-control" id="Policy" name="Policy">
  <option value="0">SuperAdmin</option>
  <option value="1">Admin</option>
  <option value="2">User</option>
  <option value="3">ClientAdmin</option>
  <option value="4">ClientUser</option>
</select>

Desired Results:
<select class="form-control" id="Policy" name="Policy">
  <option value="SuperAdmin">SuperAdmin</option>
  <option value="Admin">Admin</option>
  <option value="User">User</option>
  <option value="ClientAdmin">ClientAdmin</option>
  <option value="ClientUser">ClientUser</option>
</select>

Answer 1

如果您只需要SuperAdmin，您可以定义以下扩展:

public static class ExtensionMethods
{
    public static IEnumerable<SelectListItem> GetEnumValueSelectList<TEnum>(this IHtmlHelper htmlHelper) where TEnum : struct
    {
        return new SelectList(Enum.GetValues(typeof(TEnum)).OfType<Enum>()
            .Select(x =>
                new SelectListItem
                {
                    Text = x.ToString(),
                    Value = x.ToString()
                }), "Value", "Text");
    }       
}

和用法:

<select asp-items="Html.GetEnumValueSelectList<PolicyEnum>()" class="form-control"></select>

如果您需要[EnumMember(Value = "Admin")]，您可以尝试

public static class ExtensionMethods
{
    public static IEnumerable<SelectListItem> GetEnumMemberSelectList<TEnum>(this IHtmlHelper htmlHelper) where TEnum : struct
    {
        return new SelectList(Enum.GetValues(typeof(TEnum)).OfType<Enum>()
            .Select(x =>
                new SelectListItem
                {
                    Text = x.EnumMemberValue(),
                    Value = x.ToString()
                }), "Value", "Text");
    }

    public static string EnumMemberValue(this Enum value)
    {
        FieldInfo field = value.GetType().GetField(value.ToString());

        EnumMemberAttribute attribute
                = Attribute.GetCustomAttribute(field, typeof(EnumMemberAttribute))
                    as EnumMemberAttribute;

        return attribute == null ? value.ToString() : attribute.Value;
    }
}