Question

I have a HtmlHelper extension method that I would like to apply some logic to before execution. I suppose I’m looking for behaviour similar to Action Filters, abut I thought I could do this by applying an Attribute to a method without the need of a Filter Context.

This is my extension method:

[MyHelperAttribute]
public static string MyHelperMethod(this HtmlHelper html, string text)
{
    TagBuilder tag = new TagBuilder("a");

    return tag.ToString();
}

where this is the definition of the Attribute:

[AttributeUsage(AttributeTargets.Method)]
public class MyHelperAttribute: Attribute
{        
    public MyHelperAttribute()
    {
        // get user 
        // if user has permission, execute extension method
        // else return empty string
    }
}

The problem is that it’s not firing. The code inside the MyHelperAttribute constructor never executes. Can somebody tell me why this isn’t working or what I can do to get it to work?

On a side note, is this a decent way to manage the generation of secure links? Is there a better way?

Thanks

Dave

Answer 1

That’s not how attributes work. They simply provide some metadata at compile time. At runtime, some code could use Reflection to find the attribute. At that time, if there were a method on the attribute, it’s possible you could run it to do something.