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[英]How to create a custom athorization attribute in asp.net mvc5?
[英]ASP.NET MVC5 Custom Attribute on Parameter is empty
我有一个自定义属性,正在使用:
public class Plus.ViewModels {
[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Class | AttributeTargets.Constructor, AllowMultiple = true)]
public class ExcludeFilterAttribute : Attribute
{
public string FilterToExclude { get; private set; }
public ExcludeFilterAttribute(string filterToExclude)
{
this.FilterToExclude = filterToExclude;
}
}
}
我在控制器的操作参数上使用它,如下所示:
public class MyController
{
public ActionResult AggregationClientBase([ExcludeFilter("Categories")] AggregationFiltersViewModel filters)
{
return View(filters);
}
}
然后,我想像这样在View中读取自定义属性的值:Type type = Model.GetType();
@model AggregationFiltersViewModel
@{
Type type = Model.GetType();
ExcludeFilterAttribute[] AttributeArray = (ExcludeFilterAttribute[])type.GetCustomAttributes(typeof(ExcludeFilterAttribute), false);
ExcludeFilterAttribute fa = AttributeArray[0];
}
然后
@if (fa.FilterToExclude != "Categories")
{
<th>Category:</th>
<td>@Html.DropDownListFor(m => m.SelectedCategoryId, Model.Categories)</td>
}
但是,自定义属性的数组为空,因此出现以下错误:
Index was outside the bounds of the array. System.IndexOutOfRangeException: Index was outside the bounds of the array.
如何获取自定义属性的值? 我知道我只能传递值模型变量,但是当我要排除的集合很大时,使用自定义属性会更容易。
您正在尝试从模型获取属性,但它是在控制器的AggregationClientBase
方法内部定义的。
所以:
var controllerType = typeof(YourController);
var method = controllerType.GetMethod("AggregationClientBase");
var parameter = method.GetParameters().First(p => p.Name == "filters");
var fa = parameter.GetCustomAttributes(typeof(ExcludeFilterAttribute), false)
.First() as ExcludeFilterAttribute;
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