CODEWITHSUNDEEP
c#asp.netrazorasp.net-mvc-5custom-attributes
Rhys Stephens
Rhys Stephens

Reputation: 899

ASP.NET MVC5 Custom Attribute on Parameter is empty

I have a custom attribute I am using:

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;
        }
    }
}

I am using it on the parameter to a Controller's action like so:

public class MyController 
{
     public ActionResult AggregationClientBase([ExcludeFilter("Categories")] AggregationFiltersViewModel filters)
     {
         return View(filters);
     }
}

I then want to read the value of the custom attribute in the View like this: Type type = Model.GetType();

@model AggregationFiltersViewModel
@{
    Type type = Model.GetType();
    ExcludeFilterAttribute[] AttributeArray = (ExcludeFilterAttribute[])type.GetCustomAttributes(typeof(ExcludeFilterAttribute), false);

    ExcludeFilterAttribute fa = AttributeArray[0];   
}

Then

@if (fa.FilterToExclude != "Categories")           
{
    <th>Category:</th>
    <td>@Html.DropDownListFor(m => m.SelectedCategoryId, Model.Categories)</td>
}

However, the array of custom attributes is empty, so I get the following error:

Index was outside the bounds of the array. System.IndexOutOfRangeException: Index was outside the bounds of the array.

How can I get the value of the custom attribute? I know I can just pass values model variables, but using a custom attribute makes is easier when I have a large collection to exclude.

Upvotes: 0

Views: 495

Answers (1)

user2160375
user2160375

Reputation:

You are trying to get attribute from model, but it is defined inside method AggregationClientBase in your controller.

So:

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;

Upvotes: 1

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