Lor*_*mon 8 c# asp.net-mvc enums enum-flags
我有一个枚举属性,我试图通过复选框设置其值.枚举枚举,当用户选择多个选项时,我希望该属性连接所有选定的标志.
我尝试为每个枚举值添加一个复选框,并为每个复选框指定相同的名称.在回发期间,检索第一个选定的标志但不与其他标志连接.
如果不为每个标志分别拥有单独的属性,我可以以某种方式修复
public class HomeModel
{
public Fruit MyFruits { get; set; }
}
[Flags] public enum Fruit
{
Love = 1,
Joy = 2,
Peace = 4,
Patience = 8,
Kindness = 16,
Goodness = 32,
Faithfulness = 64,
Gentleness = 128,
SelfControl = 256
}
@model EnumFlagTest.Models.HomeModel
@{
Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
<div>
@using (Html.BeginForm())
{
<h1>Fruits</h1>
<div><label>@EnumFlagTest.Models.Fruit.Love.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Love)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Love) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Joy.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Joy)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Joy) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Peace.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Peace)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Peace) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Patience.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Patience)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Patience) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Kindness.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Kindness)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Kindness) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Goodness.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Goodness)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Goodness) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Faithfulness.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Faithfulness)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Faithfulness) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.Gentleness.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.Gentleness)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.Gentleness) ? "checked" : String.Empty) /></label></div>
<div><label>@EnumFlagTest.Models.Fruit.SelfControl.ToString() <input type="checkbox" name="MyFruits" value="@((int) EnumFlagTest.Models.Fruit.SelfControl)" @(Model.MyFruits.HasFlag(EnumFlagTest.Models.Fruit.SelfControl) ? "checked" : String.Empty) /></label></div>
<input type="submit" value="GO" />
}
</div>
</body>
</html>
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult Index()
{
HomeModel model = new HomeModel();
model.MyFruits = Fruit.Love | Fruit.Joy | Fruit.Peace | Fruit.Patience;
return View(model);
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Index(HomeModel returnData)
{
return View(returnData);
}
如果您检查POST主体是否已发送数据,则无法正确选取数据.这是因为MVC没有很好地处理标志枚举.有人谁回答过类似的问题说明如下:
一般来说,我在设计视图模型时避免使用枚举,因为它们不能与ASP.NET MVC的助手和开箱即用的模型绑定器一起使用.它们在您的域模型中非常精细,但对于视图模型,您可以使用其他类型.
在那里,回答问题的人还提供了如何绑定标志枚举的完整答案.你基本上需要做的是创建自己的自定义模型绑定器,它可以处理标志枚举.在另一篇名为ASP.Net MVC Flag Enumeration Model Binder的文章中,我找到了一个例子,我将复制相关代码.
添加一个名为CustomModelBinder如下的类:
public class CustomModelBinder : DefaultModelBinder
{
protected override object GetPropertyValue(
ControllerContext controllerContext,
ModelBindingContext bindingContext,
PropertyDescriptor propertyDescriptor,
IModelBinder propertyBinder)
{
var propertyType = propertyDescriptor.PropertyType;
// Check if the property type is an enum with the flag attribute
if (propertyType.IsEnum && propertyType.GetCustomAttributes(true).Any())
{
var providerValue = bindingContext.ValueProvider
.GetValue(bindingContext.ModelName);
if (providerValue != null)
{
var value = providerValue.RawValue;
if (value != null)
{
// In case it is a checkbox list/dropdownlist/radio
// button list
if (value is string[])
{
// Create flag value from posted values
var flagValue = ((string[])value)
.Aggregate(0, (acc, i)
=> acc | (int)Enum.Parse(propertyType, i));
return Enum.ToObject(propertyType, flagValue);
}
// In case it is a single value
if (value.GetType().IsEnum)
{
return Enum.ToObject(propertyType, value);
}
}
}
}
return base.GetPropertyValue(controllerContext,
bindingContext,
propertyDescriptor,
propertyBinder);
}
}
然后在Global.asax.cs Application_Start方法中注册自定义模型绑定器,如下所示:
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
RegisterGlobalFilters(GlobalFilters.Filters);
RegisterRoutes(RouteTable.Routes);
// Register custom flag enum model binder
ModelBinders.Binders.DefaultBinder = new CustomModelBinder();
}
这应该工作.
资料来源:http://itq.nl/asp-net-mvc-flag-enumeration-model-binder/
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