C#MVC:DropDownListFor将枚举绑定到整数模型字段

时间:2013-04-09 09:22:57

标签: c# asp.net-mvc drop-down-menu enums

如何将枚举绑定到整数类型的模型字段?

我尝试了一些扩展方法,但是它们并没有做得很好,因为所有方法都需要模型字段为给定的枚举类型...

这是我的来源(模特和枚举):

型号:

public class Einheit
{
    public Einheit()
    {
        Id = Guid.NewGuid();
    }

    public Guid Id { get; set; }
    public short TypeOfSomething { get; set; }
    public long Verwendungszweck { get; set; }
}

枚举:

public enum Einheitsart
{
    Type1 = 0,
    Type2 = 1,
    Type3 = 2,
    Type4 = 3,
    Type5 = 4,
    Type6 = 5
}

我希望值从0到6(为了能够在我的模型中保存整数),但是DropDownList应该将文本“Type1”显示为“Type6”......

我遇到的问题是将枚举转换为有效的SelectList。

谢谢!

2 个答案:

答案 0 :(得分:1)

尝试我创建的以下帮助程序。

我的博客上可以看到完整的详细信息:

http://www.ninjanye.co.uk/2012/01/creating-dropdown-list-from-enum-in.html

http://jnye.co/Posts/4/creating-a-dropdown-list-from-an-enum-in-mvc-and-c%23

public static class EnumHelper  
{  
    //Creates a SelectList for a nullable enum value  
    public static SelectList SelectListFor<T>(T? selected)  
        where T : struct  
    {  
        return selected == null ? SelectListFor<T>()  
                                : SelectListFor(selected.Value);  
    }  

    //Creates a SelectList for an enum type  
    public static SelectList SelectListFor<T>() where T : struct  
    {  
        Type t = typeof (T);  
        if (t.IsEnum)  
        {  
            var values = Enum.GetValues(typeof(T)).Cast<enum>()  
                             .Select(e => new { Id = Convert.ToInt32(e), Name = e.GetDescription() });  

            return new SelectList(values, "Id", "Name");  
        }  
        return null;  
    }  

    //Creates a SelectList for an enum value  
    public static SelectList SelectListFor<T>(T selected) where T : struct   
    {  
        Type t = typeof(T);  
        if (t.IsEnum)  
        {  
            var values = Enum.GetValues(t).Cast<Enum>()  
                             .Select(e => new { Id = Convert.ToInt32(e), Name = e.GetDescription() });  

            return new SelectList(values, "Id", "Name", Convert.ToInt32(selected));  
        }  
        return null;  
    }   

    // Get the value of the description attribute if the   
    // enum has one, otherwise use the value.  
    public static string GetDescription<TEnum>(this TEnum value)  
    {  
        FieldInfo fi = value.GetType().GetField(value.ToString());  

        if (fi != null)  
        {  
            DescriptionAttribute[] attributes =  
             (DescriptionAttribute[])fi.GetCustomAttributes(  
    typeof(DescriptionAttribute),  
    false);  

            if (attributes.Length > 0)  
            {  
                 return attributes[0].Description;  
            }  
        }  

        return value.ToString();  
    }  
}  

要使用它,只需使用以下代码:

//If you don't have an enum value use the type  
ViewBag.DropDownList = EnumHelper.SelectListFor<MyEnum>();  

//If you do have an enum value use the value (the value will be marked as selected)  
ViewBag.DropDownList = EnumHelper.SelectListFor(myEnumValue); 

注意:通过在枚举中添加description属性,它将使用它作为下拉列表的显示文本:

public enum Einheitsart
{
    Type1 = 0,
    [Description("2nd Type")]
    Type2 = 1,
    Type3 = 2,
    Type4 = 3,
    Type5 = 4,
    Type6 = 5
}

答案 1 :(得分:0)

您可以枚举所有枚举值并为每个枚举值创建SelectListItems。这应该有效:

var selectList = new List<SelectListItem>();
foreach(Einheitsart art in Enum.GetValues(typeof(Einheitsart)))
{
    selectList.Add(new SelectListItem() { Value = (int)art, Text = art.ToString() })
}