How to create duplicate allowed attributes

Question

I'm using a custom attribute inherited from an attribute class. I'm using it like this:

[MyCustomAttribute("CONTROL")] [MyCustomAttribute("ALT")] [MyCustomAttribute("SHIFT")] [MyCustomAttribute("D")] public void setColor() {  } 

But the "Duplicate 'MyCustomAttribute' attribute" error is shown.
How can I create a duplicate allowed attribute?

Answer 1

Stick an AttributeUsage attribute onto your Attribute class (yep, that's mouthful) and set AllowMultiple to true:

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public sealed class MyCustomAttribute: Attribute 

Answer 2

AttributeUsageAttribute ;-p

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MyAttribute : Attribute {} 

Note, however, that if you are using ComponentModel (TypeDescriptor), it only supports one attribute instance (per attribute type) per member; raw reflection supports any number...