我正在尝试使用Html。下拉列表扩展方法,但不知道如何与枚举一起使用它。
假设我有一个这样的枚举:
public enum ItemTypes
{
Movie = 1,
Game = 2,
Book = 3
}
我如何去创建一个下拉与这些值使用Html。下拉列表扩展方法?
或者我最好的办法是简单地创建一个for循环并手动创建Html元素?
我正在尝试使用Html。下拉列表扩展方法,但不知道如何与枚举一起使用它。
假设我有一个这样的枚举:
public enum ItemTypes
{
Movie = 1,
Game = 2,
Book = 3
}
我如何去创建一个下拉与这些值使用Html。下拉列表扩展方法?
或者我最好的办法是简单地创建一个for循环并手动创建Html元素?
当前回答
//// ViewModel
public class RegisterViewModel
{
public RegisterViewModel()
{
ActionsList = new List<SelectListItem>();
}
public IEnumerable<SelectListItem> ActionsList { get; set; }
public string StudentGrade { get; set; }
}
//// Enum Class
public enum GradeTypes
{
A,
B,
C,
D,
E,
F,
G,
H
}
////Controller action
public ActionResult Student()
{
RegisterViewModel vm = new RegisterViewModel();
IEnumerable<GradeTypes> actionTypes = Enum.GetValues(typeof(GradeTypes))
.Cast<GradeTypes>();
vm.ActionsList = from action in actionTypes
select new SelectListItem
{
Text = action.ToString(),
Value = action.ToString()
};
return View(vm);
}
////// View Action
<div class="form-group">
<label class="col-lg-2 control-label" for="hobies">Student Grade:</label>
<div class="col-lg-10">
@Html.DropDownListFor(model => model.StudentGrade, Model.ActionsList, new { @class = "form-control" })
</div>
其他回答
这是符文和价格的答案改变使用Enum int值作为ID。
示例枚举:
public enum ItemTypes
{
Movie = 1,
Game = 2,
Book = 3
}
扩展方法:
public static SelectList ToSelectList<TEnum>(this TEnum enumObj)
{
var values = from TEnum e in Enum.GetValues(typeof(TEnum))
select new { Id = (int)Enum.Parse(typeof(TEnum), e.ToString()), Name = e.ToString() };
return new SelectList(values, "Id", "Name", (int)Enum.Parse(typeof(TEnum), enumObj.ToString()));
}
用法示例:
<%= Html.DropDownList("MyEnumList", ItemTypes.Game.ToSelectList()) %>
记住导入包含Extension方法的命名空间
<%@ Import Namespace="MyNamespace.LocationOfExtensionMethod" %>
生成的HTML示例:
<select id="MyEnumList" name="MyEnumList">
<option value="1">Movie</option>
<option selected="selected" value="2">Game</option>
<option value="3">Book </option>
</select>
请注意,用于调用ToSelectList的项就是选中的项。
@Html.DropdownListFor(model=model->Gender,new List<SelectListItem>
{
new ListItem{Text="Male",Value="Male"},
new ListItem{Text="Female",Value="Female"},
new ListItem{Text="--- Select -----",Value="-----Select ----"}
}
)
这里是Martin Faartoft的变种,你可以放自定义标签,这对本地化很好。
public static class EnumHtmlHelper
{
public static SelectList ToSelectList<TEnum>(this TEnum enumObj, Dictionary<int, string> customLabels)
where TEnum : struct, IComparable, IFormattable, IConvertible
{
var values = from TEnum e in Enum.GetValues(typeof(TEnum))
select new { Id = e, Name = customLabels.First(x => x.Key == Convert.ToInt32(e)).Value.ToString() };
return new SelectList(values, "Id", "Name", enumObj);
}
}
视图中使用:
@Html.DropDownListFor(m => m.Category, Model.Category.ToSelectList(new Dictionary<int, string>() {
{ 1, ContactResStrings.FeedbackCategory },
{ 2, ContactResStrings.ComplainCategory },
{ 3, ContactResStrings.CommentCategory },
{ 4, ContactResStrings.OtherCategory }
}), new { @class = "form-control" })
@Html.ValidationMessageFor(m => m.Category)
好吧,我真的是姗姗姗迟了,但无论如何,我已经在博客上讨论了这个主题,在这个主题中我创建了一个EnumHelper类,它可以实现非常简单的转换。
http://jnye.co/Posts/4/creating-a-dropdown-list-from-an-enum-in-mvc-and-c%23
在你的控制器中:
//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(MyEnum.MyEnumValue);
在您看来:
@Html.DropDownList("DropDownList")
@* OR *@
@Html.DropDownListFor(m => m.Property, ViewBag.DropDownList as SelectList, null)
helper类:
public static class EnumHelper
{
// Get the value of the description attribute if the
// enum has one, otherwise use the value.
public static string GetDescription<TEnum>(this TEnum value)
{
var fi = value.GetType().GetField(value.ToString());
if (fi != null)
{
var attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
if (attributes.Length > 0)
{
return attributes[0].Description;
}
}
return value.ToString();
}
/// <summary>
/// Build a select list for an enum
/// </summary>
public static SelectList SelectListFor<T>() where T : struct
{
Type t = typeof(T);
return !t.IsEnum ? null
: new SelectList(BuildSelectListItems(t), "Value", "Text");
}
/// <summary>
/// Build a select list for an enum with a particular value selected
/// </summary>
public static SelectList SelectListFor<T>(T selected) where T : struct
{
Type t = typeof(T);
return !t.IsEnum ? null
: new SelectList(BuildSelectListItems(t), "Text", "Value", selected.ToString());
}
private static IEnumerable<SelectListItem> BuildSelectListItems(Type t)
{
return Enum.GetValues(t)
.Cast<Enum>()
.Select(e => new SelectListItem { Value = e.ToString(), Text = e.GetDescription() });
}
}
我想以一种不同的方式回答这个问题,用户不需要在控制器或Linq表达式中做任何事情。这种方式……
我有一个ENUM
public enum AccessLevelEnum
{
/// <summary>
/// The user cannot access
/// </summary>
[EnumMember, Description("No Access")]
NoAccess = 0x0,
/// <summary>
/// The user can read the entire record in question
/// </summary>
[EnumMember, Description("Read Only")]
ReadOnly = 0x01,
/// <summary>
/// The user can read or write
/// </summary>
[EnumMember, Description("Read / Modify")]
ReadModify = 0x02,
/// <summary>
/// User can create new records, modify and read existing ones
/// </summary>
[EnumMember, Description("Create / Read / Modify")]
CreateReadModify = 0x04,
/// <summary>
/// User can read, write, or delete
/// </summary>
[EnumMember, Description("Create / Read / Modify / Delete")]
CreateReadModifyDelete = 0x08,
/*/// <summary>
/// User can read, write, or delete
/// </summary>
[EnumMember, Description("Create / Read / Modify / Delete / Verify / Edit Capture Value")]
CreateReadModifyDeleteVerify = 0x16*/
}
现在我可以使用这个enum简单地创建一个下拉列表。
@Html.DropDownList("accessLevel",new SelectList(AccessLevelEnum.GetValues(typeof(AccessLevelEnum))),new { @class = "form-control" })
OR
@Html.DropDownListFor(m=>m.accessLevel,new SelectList(AccessLevelEnum.GetValues(typeof(AccessLevelEnum))),new { @class = "form-control" })
如果你想让一个索引被选中,那么试试这个
@Html.DropDownListFor(m=>m.accessLevel,new SelectList(AccessLevelEnum.GetValues(typeof(AccessLevelEnum)) , AccessLevelEnum.NoAccess ),new { @class = "form-control" })
这里我使用了AccessLevelEnum。NoAccess作为默认选择下拉菜单的额外参数。