如何为枚举制作默认的编辑器模板？

Question

如何为枚举创建默认编辑器模板？我的意思是:我可以做这样的事情:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Enum>" %> 
<% -- any code to read the enum and write a dropdown -->

并将其放在EditorTemplates文件夹下的名称下Enum.ascx？

这是我尝试过的问题的解决方法,但这不是我需要的.

这是我的枚举:

public enum GenderEnum
{
    /// <summary>
    /// Male
    /// </summary>
    [Description("Male Person")]
    Male,

    /// <summary>
    /// Female
    /// </summary>
    [Description("Female Person")]
    Female
}

我制作了一个名为的模板GenderEnum.acsx并将其放入Shared/EditorTemplates文件夹中.这是模板:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<AlefTech.HumanResource.Core.GenderEnum>" %>
<%@ Import Namespace="AlefTech.HumanResource.WebModule.Classes" %>
<%=Html.DropDownListFor(m => m.GetType().Name, Model.GetType()) %>

当然这个方法是我自己的:

public static class HtmlHelperExtension
    {
        public static MvcHtmlString DropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType)
        {
            List<SelectListItem> list = new List<SelectListItem>();
            Dictionary<string, string> enumItems = enumType.GetDescription();
            foreach (KeyValuePair<string, string> pair in enumItems)
                list.Add(new SelectListItem() { Value = pair.Key, Text = pair.Value });
            return htmlHelper.DropDownListFor(expression, list);
        }

        /// <summary>
        /// return the items of enum paired with its descrtioption.
        /// </summary>
        /// <param name="enumeration">enumeration type to be processed.</param>
        /// <returns></returns>
        public static Dictionary<string, string> GetDescription(this Type enumeration)
        {
            if (!enumeration.IsEnum)
            {
                throw new ArgumentException("passed type must be of Enum type", "enumerationValue");
            }

            Dictionary<string, string> descriptions = new Dictionary<string, string>();
            var members = enumeration.GetMembers().Where(m => m.MemberType == MemberTypes.Field);

            foreach (MemberInfo member in members)
            {
                var attrs = member.GetCustomAttributes(typeof(DescriptionAttribute), false);
                if (attrs.Count() != 0)
                    descriptions.Add(member.Name, ((DescriptionAttribute)attrs[0]).Description);
            }
            return descriptions;
        }

    }

然而,尽管这对我有用,但这不是我所要求的.相反,我需要以下工作:

代码Shared\EditorTemplates\Enum.acsx:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Enum>" %>
<%@ Import Namespace="System.Web.Mvc.Html" %>
<%@ Import Namespace="WhereMyExtentionMethod" %>
<%=Html.DropDownListFor(m => m.GetType().Name, Model.GetType()) %>

有了这个,我就不用再为每个枚举制作模板了.

Answer 1

迟到回答,但我希望这有助于其他人.理想情况下,您希望所有枚举按惯例使用您的Enum模板,而不是每次都指定UIHint,您可以通过创建这样的自定义模型元数据提供程序来实现:

using System;
using System.Collections.Generic;
using System.Web.Mvc;

public class CustomMetadataProvider : DataAnnotationsModelMetadataProvider
{
    protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName) {
        var mm = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);
        if (modelType.IsEnum && mm.TemplateHint == null) {
            mm.TemplateHint = "Enum";
        }
        return mm;
    }
}

然后只需在Global.asax.cs的Application_Start方法中注册它:

ModelMetadataProviders.Current = new CustomMetadataProvider();

现在,默认情况下,所有枚举属性都将使用您的枚举模板.

Answer 2

谢谢你们的贡献
Yngvebn,我之前尝试过你的解决方案(在你的最后评论中),但我唯一没做的就是<dynamic>,我用的<Enum>是通用类型.

最后解决方案是:
创建一个名为Enum.acsx的模板,并将其放在Views\Shared\EditorTemplates下

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<dynamic>" %>
<%@ Import Namespace="System.Web.Mvc.Html" %>
<%@ Import Namespace="the extension methods namespace" %>
<% Enum model = (Enum)Model; %>
<%=Html.DropDownList(model.GetType().Name,model.GetType())%>

在您的实体中:

public class Person
{
  [UIHint("Enum")]
  public GenderEnum Gender{get;set;}
}

public Enum GenderEnum
{
 [Description("Male Person")]
 Male,
 [Description("Female Person")]
 Female
}

并且还有扩展方法:

public static class HtmlHelperExtension
    {
        public static MvcHtmlString DropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType)
        {
            List<SelectListItem> list = new List<SelectListItem>();
            Dictionary<string, string> enumItems = enumType.GetDescription();
            foreach (KeyValuePair<string, string> pair in enumItems)
                list.Add(new SelectListItem() { Value = pair.Key, Text = pair.Value });
            return htmlHelper.DropDownListFor(expression, list);
        }

        /// <summary>
        /// return the items of enum paired with its descrtioption.
        /// </summary>
        /// <param name="enumeration">enumeration type to be processed.</param>
        /// <returns></returns>
        public static Dictionary<string, string> GetDescription(this Type enumeration)
        {
            if (!enumeration.IsEnum)
            {
                throw new ArgumentException("passed type must be of Enum type", "enumerationValue");
            }

            Dictionary<string, string> descriptions = new Dictionary<string, string>();
            var members = enumeration.GetMembers().Where(m => m.MemberType == MemberTypes.Field);

            foreach (MemberInfo member in members)
            {
                var attrs = member.GetCustomAttributes(typeof(DescriptionAttribute), false);
                if (attrs.Count() != 0)
                    descriptions.Add(member.Name, ((DescriptionAttribute)attrs[0]).Description);
            }
            return descriptions;
        }

    }

Answer 3

这是我为此做的一个帮手..在你的视图中你可以简单地做:

<%= Html.DropDownForEnum<MyEnum>("some-name-for-dropdown", MyEnum.TheFirstValue) %>

对于实际下拉列表中的文本,它将在资源文件中查找与枚举名称匹配的资源,否则只需编写实际的Enumtext本身.

public static MvcHtmlString DropDownForEnum<T>(this HtmlHelper h, string name, T selectedValue)
{
    Type enumType = typeof(T);
    Tag t = new Tag("select").With("name", name).And("id", name);

    foreach (T val in Enum.GetValues(enumType))
    {
        string enumText = Resources.ResourceManager.GetString(val.ToString());
        if (String.IsNullOrEmpty(enumText)) enumText = val.ToString();
        Tag option = new Tag("option").With("value", (val).ToString()).AndIf(val.Equals(selectedValue), "selected", "selected").WithText(enumText);
        t.Append(option);
    }
    return MvcHtmlString.Create(t.ToString());
}

如果你想要它没有重写,你还需要我重载的Tag类.

public class Tag : TagBuilder
{
public Tag (string TagName): base(TagName)
{

}

public Tag Append(Tag innerTag)
{
    base.InnerHtml += innerTag.ToString();
    return this;
}

public Tag WithText(string text)
{

    base.InnerHtml += text;
    return this;
}

public Tag With(Tag innerTag)
{
    base.InnerHtml = innerTag.ToString();
    return this;
}

public Tag With(string attributeName, string attributeValue)
{
    base.Attributes.Add(attributeName, attributeValue);
    return this;
}

public Tag And(string attributeName, string attributeValue)
{
    base.Attributes.Add(attributeName, attributeValue);
    return this;
}


public Tag AndIf(bool condition, string attributeName, string attributeValue)
{
    if(condition)
        base.Attributes.Add(attributeName, attributeValue);
    return this;
}
}

Answer 4

Nour Sabony,我修改了你的版本,也支持资源本地化.因此,我将DescriptionAttribute更改为DataAnnotations命名空间的DisplayAttribute

    public static MvcHtmlString DropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType)
    {
        List<SelectListItem> list = new List<SelectListItem>();
        Dictionary<string, string> enumItems = enumType.GetDisplayNames(htmlHelper.ViewContext.HttpContext);
        foreach (KeyValuePair<string, string> pair in enumItems)
            list.Add(new SelectListItem() { Value = pair.Key, Text = pair.Value });
        return htmlHelper.DropDownListFor(expression, list);
    }

    /// <summary>
    /// return the items of enum paired with its DisplayName.
    /// </summary>
    /// <param name="enumeration">enumeration type to be processed.</param>
    /// <returns></returns>
    public static Dictionary<string, string> GetDisplayNames(this Type enumeration, HttpContextBase httpContext)
    {
        if (!enumeration.IsEnum)
        {
            throw new ArgumentException("passed type must be of Enum type", "enumerationValue");
        }

        Dictionary<string, string> displayNames = new Dictionary<string, string>();
        var members = enumeration.GetMembers().Where(m => m.MemberType == MemberTypes.Field);

        foreach (MemberInfo member in members)
        {
            var attrs = member.GetCustomAttributes(typeof(DisplayAttribute), false);
            if (attrs.Count() != 0)
                if (((DisplayAttribute)attrs[0]).ResourceType != null)
                {
                    displayNames.Add(member.Name, ((DisplayAttribute)attrs[0]).GetName(););
                }
                else
                {
                    displayNames.Add(member.Name, ((DisplayAttribute)attrs[0]).Name);
                }
        }
        return displayNames;
    }

枚举的定义现在必须如下所示:

public enum Gender
{
    [Display(Name = "Male", ResourceType = typeof(mynamespace.App_LocalResources.Shared))]
    Male = 1,

    [Display(Name = "Female", ResourceType = typeof(mynamespace.App_LocalResources.Shared))]
    Female = 2,

}

它可以以相同的方式在视图中使用,例如(Razor):

@Html.DropDownListFor(model => model.Gender, typeof(Gender))

希望这有助于某人!