using System;
using System.Reflection;

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Assembly, AllowMultiple = true, Inherited = false)]
class HelpAttribute : Attribute
{
	public string field = "field";

	public string Help
	{
		get;
		set;
	}

	public HelpAttribute()
	{
		Help = "no help";
	}

	public HelpAttribute(string help)
	{	
		this.Help = help;
	}
}

[Help]
class ClassWithCustomAttribute
{

	public ClassWithCustomAttribute()
	{
		ReadAttributes();
		// Method invoked only when debugging
		MethodDebug();
	}

	[Obsolete("This method should not be used anymore!", true)]
	public void Method0()
    { 
		// do smth
	}

	[System.Diagnostics.Conditional("Debug")]
	public void MethodDebug()
	{
		Console.WriteLine("Method for debug!");
	}

	protected void ReadAttributes()
	{
	    // if  AllowMultiple = false but inherited is true the base class Help is overridden by the Derive class Help attribute.
		Console.WriteLine("Assigned attributes of "+this+": ");
		foreach(HelpAttribute attr in this.GetType().GetCustomAttributes(true))
		{
			Console.WriteLine("\tHelp: \t" + attr.Help);
			Console.WriteLine("\tField: \t"+attr.field);			
		}
	}
}

[Help(field = "Some help field")]
class DerivedClassWithCustomAttribute : ClassWithCustomAttribute
{
	public DerivedClassWithCustomAttribute()
	{
		ReadAttributes();
	}
}

public class Test
{
	public static void Main()
	{

		ClassWithCustomAttribute cca = new ClassWithCustomAttribute();
		// OUTPUT:
		// Assigned attributes: 
		// 		Help: 		no help
		// 		Field: 		field

		DerivedClassWithCustomAttribute dca = new DerivedClassWithCustomAttribute();
		// OUTPUT:
		// Assigned attributes of DerivedClassWithCustomAttribute: 
		// 		Help: 	no help
		//		Field: 	Some help field
		
		// In case the Inherited option of AttributeUsage applied to HelpAttribute 
		// we would get following output when invoke ctor of DerivedClassWithCustomAttribute:
		// OUTPUT:
		// Assigned attributes of DerivedClassWithCustomAttribute: 
		// 		Help: 	no help
		// 		Field: 	Some help field
		// 		Help: 	no help
		// 		Field: 	field
		
	}
}