[2014-09-21]如何在 Asp.net Mvc 开发过程中更好的使用Enum

场景描述

在web开发过程中，有时候需要根据Enum类型生成下拉菜单；

有时候在输出枚举类型的时候，又希望输出对应的更具描述性的字符串。

喜欢直接用中文的请无视本文

不多说，直接看代码。

以下代码借鉴自http://stackoverflow.com/

本文针对 Aspnet Mvc 4 开发而言

Enum定义

using System.ComponentModel;

namespace xxxxx.yyyyy

{

    public enum EN_ArticleType

    {

        [Description("软装家饰")]

        RuanZhuang=1,

        [Description("家居风水")]

        FengShui,

        [Description("装修技巧")]

        JiQiao,

        [Description("行业动态")]

        DongTai,

        [Description("样板美图")]

        MeiTu,

        [Description("人才招聘")]

        Jobs

    }

}

扩展HtmlHelper

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Linq;

using System.Linq.Expressions;

using System.Web.Mvc;

using System.Web.Mvc.Html;

namespace xxxx.ExtendMethods

{

    public static class HtmlHelperUtils

    {

        /// <summary>

        /// Creates the DropDown List (HTML Select Element) from LINQ

        /// Expression where the expression returns an Enum type.

        /// </summary>

        /// <typeparam name="TModel">The type of the model.</typeparam>

        /// <typeparam name="TProperty">The type of the property.</typeparam>

        /// <param name="htmlHelper">The HTML helper.</param>

        /// <param name="expression">The expression.</param>

        /// <returns></returns>

        public static MvcHtmlString DropDownListForEnum<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper,

            Expression<Func<TModel, TProperty>> expression)

            where TModel : class

        {

            return htmlHelper.DropDownListForEnum(expression, null);

        }

        public static MvcHtmlString DropDownListForEnum<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper,

            Expression<Func<TModel, TProperty>> expression, object htmlAttributes)

            where TModel : class

        {

            TProperty value = htmlHelper.ViewData.Model == null

                ? default(TProperty)

                : expression.Compile()(htmlHelper.ViewData.Model);

            string selected = value == null ? String.Empty : value.ToString();

            if (htmlAttributes == null)

            {

                return htmlHelper.DropDownListFor(expression, createSelectList(expression.ReturnType, selected));

            }

            else

            {

                return htmlHelper.DropDownListFor(expression, createSelectList(expression.ReturnType, selected), htmlAttributes);

            }

        }

        /// <summary>

        /// Creates the select list.

        /// </summary>

        /// <param name="enumType">Type of the enum.</param>

        /// <param name="selectedItem">The selected item.</param>

        /// <returns></returns>

        private static IEnumerable<SelectListItem> createSelectList(Type enumType, string selectedItem)

        {

            return (from object item in Enum.GetValues(enumType)

                    let fi = enumType.GetField(item.ToString())

                    let attribute = fi.GetCustomAttributes(typeof(DescriptionAttribute), true).FirstOrDefault()

                    let title = attribute == null ? item.ToString() : ((DescriptionAttribute)attribute).Description

                    select new SelectListItem

                    {

                        Value = item.ToString(),

                        Text = title,

                        Selected = selectedItem == item.ToString()

                    }).ToList();

        }

    }

}

视图层输出下拉菜单

 @Html.DropDownListForEnum(model => model.Type, new { @class = "col-sm-2" })

扩展Enum

using System;

using System.ComponentModel;

using System.Reflection;

namespace xxxx.ExtendMethods

{

    public static class EnumUtils

    {

        public static string GetEnumDescription(this Enum value)

        {

            FieldInfo fi = value.GetType().GetField(value.ToString());

            DescriptionAttribute[] attributes =

                (DescriptionAttribute[])fi.GetCustomAttributes(

                typeof(DescriptionAttribute),

                false);

            if (attributes != null &&

                attributes.Length > 0)

                return attributes[0].Description;

            else

                return value.ToString();

        }

    }

}

输出Enum value对应的Description

@item.Type.GetEnumDescription()  //item是实体，Type是EN_ArticleType类型的属性

结束

请自行尝试。

：）

巴特西

[2014-09-21]如何在 Asp.net Mvc 开发过程中更好的使用Enum

场景描述

Enum定义

扩展HtmlHelper

视图层输出下拉菜单

扩展Enum

输出Enum value对应的Description

结束

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