MVC3,EF,根据枚举生成下拉框,获取枚举的自定义属性值.自动扩展，快速开发。

项目中经常用到枚举,根据枚举定义的下拉框比如用户状态等,就非常麻烦,所以写个根据枚举项自动生成下拉框,并扩展htmlhelper类去显示枚举的值.

定义管理员状态枚举值：

 1 /// <summary>

 2     /// 管理员状态

 3     /// </summary>

 4     public enum ManageState

 5     {

 6         /// <summary>

 7         /// 正常

 8         /// </summary>

 9         [Display(Name="正常")]

10         Normal = 0,

11         /// <summary>

12         /// 已禁用

13         /// </summary>

14         [Display(Name = "已禁用")]

15         Stop = 1

16     }

更具枚举生成下拉框：

简单helpers 方法:

@*将枚举变为下拉框*@

@helper DropEnumFor(Type enumType,string name="state",KeyValuePair<string,string>? defu=null){

    Dictionary<string, int> dir = new Dictionary<string, int>();

    var discriptType = typeof(System.ComponentModel.DataAnnotations.DisplayAttribute);

    var defultChecked = HttpContext.Current.Request["state"];

    foreach (var filed in enumType.GetFields())

    {

        if (!filed.FieldType.IsEnum) {continue;}

        var val = (int)enumType.InvokeMember(filed.Name, System.Reflection.BindingFlags.GetField, null, null, null);

        var key = "";

        var attrs=filed.GetCustomAttributes(discriptType,true);

        if (attrs.Length > 0)

        {

            key = ((DisplayAttribute)attrs[0]).Name;

        }

        else

        {

            key = filed.Name;

        }

        dir.Add(key, val);

    }

    <select id="@name" name="@name">

        @if (defu != null)

        { 

        <option value="@defu.Value.Value">@defu.Value.Key</option>

        }

            @foreach (var item in dir.OrderByDescending(p=>p.Value))

            {

                var check = string.Empty;

                if (defultChecked == item.Value.ToString())

                { check = "selected=\"true\""; }

            <option value="@item.Value" @check >@item.Key</option>

            }

        </select>

}

全局静态扩展：

 1 /// <summary>

 2        /// 获取枚举的下拉框

 3        /// </summary>

 4        /// <typeparam name="TEnum">枚举类型</typeparam>

 5        /// <param name="name">空间name属性</param>

 6        /// <param name="defaultValue">默认值</param>

 7        /// <returns>select 下拉框</returns>

 8        public static string DropEnumFor<TEnum>(this HtmlHelper helper, string name = "state", KeyValuePair<string, string>? defaultValue = null)

 9            where TEnum : struct

10        {

11            var result = new StringBuilder("<select");

12            var enumType = typeof(TEnum);

13            var defultChecked = HttpContext.Current.Request["state"];

14            Dictionary<string, int> dir = new Dictionary<string, int>();

15            var discriptType = typeof(System.ComponentModel.DataAnnotations.DisplayAttribute);

16            foreach (var filed in enumType.GetFields())

17            {

18                if (!filed.FieldType.IsEnum) { continue; }

19                var val = (int)enumType.InvokeMember(filed.Name, System.Reflection.BindingFlags.GetField, null, null, null);

20                var key = "";

21                var attrs = filed.GetCustomAttributes(discriptType, true);

22                if (attrs.Length > 0)

23                {

24                    key = ((DisplayAttribute)attrs[0]).Name;

25                }

26                else

27                {

28                    key = filed.Name;

29                }

30                dir.Add(key, val);

31            }

32            result.AppendFormat(" id=\"{0}\" name=\"{1}\">", name, name);

33            if (defaultValue != null)

34            {

35 

36            }

37            foreach (var item in dir.OrderByDescending(p => p.Value))

38            {

39                var check=string.Empty;;

40                if (defultChecked == item.Value.ToString())

41                    check = "selected=\"true\"";

42                result.AppendFormat("<option value=\"{0}\" {2}>{1}</option>", item.Value, item.Key, check);

43            }

44            result.Append("</select>");

45            return result.ToString();

46        }

47     }

扩展htmlhelper进行显示

/// <summary>

       /// 获取枚举的display属性

       /// </summary>

       /// <param name="helper"></param>

       /// <param name="state"></param>

       /// <returns></returns>

       public static string Display<TEnum>(this HtmlHelper helper, TEnum state) where TEnum : struct

       {

           var enumType = typeof(TEnum);

           var discriptType = typeof(System.ComponentModel.DataAnnotations.DisplayAttribute);

           var enumName = enumType.GetEnumName(state);

           var result = enumName;

           var attributes= enumType.GetField(enumName).GetCustomAttributes(discriptType, true);

           if (attributes.Length <= 0) return result;

           var dispay=attributes[0] as System.ComponentModel.DataAnnotations.DisplayAttribute;

           result = dispay == null ? result : dispay.Name;

           return result;

       }

使用方式
下拉框:

@Helpers.DropEnumFor(typeof(ManageState), "state", new KeyValuePair<string, string>("全部", "0"))

显示:

<span>
     [@Html.Display(item.ManageState)]
</span>

注：如果在反射时候加上缓存，效率会提升。