MemberInfo.GetCustomAttributes Method

As most of the Reflection classes, such as Type, MemberInfo, and ParameterInfo, all implement ICustomAttributeProvider, you can add some extension methods (new to C# 3.0 and Visual Basic 9.0) to extend this interface to make retrieving attributes a little easier.

For example:

[C#]

using System;
using System.Reflection;

public static class CustomAttributeProviderExtensions
{
    public static T[] GetCustomAttributes<T>(this ICustomAttributeProvider provider) where T : Attribute
    {
        return GetCustomAttributes<T>(provider, true);
    }

    public static T[] GetCustomAttributes<T>(this ICustomAttributeProvider provider, bool inherit) where T : Attribute
    {
        if (provider == null)
            throw new ArgumentNullException("provider");

        T[] attributes = provider.GetCustomAttributes(typeof(T), inherit) as T[];
        if (attributes == null)
        {   // WORKAROUND: Due to a bug in the code for retrieving attributes
            // from a dynamic generated parameter, GetCustomAttributes can return
            // an instance of an object[] instead of T[], and hence the cast above
            // will return null.

            return new T[0];
        }

        return attributes;
    }
}

This allows you to do the following:

[C#]

[Serializable]
class Program
{
    static void Main(string[] args)
    {
        SerializableAttribute[] attributes = typeof(Program).GetCustomAttributes<SerializableAttribute>();

        foreach (var attribute in attributes)
        {
            Console.WriteLine(attribute);
        }
    }
}

Which outputs the following:

SerializableAttribute