class1.cs

C#开发教程 由浅入深 配有实例 是初学者的好帮手

using System;
using System.Reflection;

namespace AttribParams
{
	public enum RegHives
	{
		HKEY_CLASSES_ROOT = 1,
		HKEY_CURRENT_USER,
		HKEY_LOCAL_MACHINE,
		HKEY_USERS,
		HKEY_CURRENT_CONFIG
	}

	public class RegKeyAttribute : Attribute
	{
//		public RegKeyAttribute(RegHives Hive, String ValueName)
		public RegKeyAttribute(String ValueName)
		{
//			this.Hive = Hive;	// defaults to 0, ie RegHives.HKEY_CLASSES_ROOT
			if (this.Hive == 0) 
				this.Hive = RegHives.HKEY_CURRENT_USER;
			this.ValueName = ValueName;
		}

		protected RegHives hive;
		public RegHives Hive
		{
			get { return hive; }
			set { hive = value; }
		}

		protected String valueName;
		public String ValueName
		{
			get { return valueName; }
			set { valueName = value; }
		}
	}

	class SomeClass
	{
		// either
		[RegKey("Foo")]
		public int Foo;

		// or
//		[RegKey("Foo", Hive = RegHives.HKEY_LOCAL_MACHINE)]
//		public int Foo;

		// Error: positional parameters cannot follow
		// named parameters.
//		[RegKey(Hive=RegHives.HKEY_LOCAL_MACHINE, "Foo")]
//		public int Foo;

		// Error: no positional parameters supplied
//		[RegKey(ValueName="Foo", Hive=RegHives.HKEY_LOCAL_MACHINE)]
//		public int Bar;
	}

	class Test
	{
		[STAThread]
		static void Main(string[] args)
		{
			Type type = Type.GetType("AttribParams.SomeClass");
			foreach (FieldInfo field in type.GetFields())
			{
				foreach (Attribute attr in 
					field.GetCustomAttributes(true))
				{
					RegKeyAttribute rka = 
						attr as RegKeyAttribute;
					if (null != rka)
					{
						Console.WriteLine(
							"{0} will be saved in"
							+ " {1}\\\\{2}", 
							field.Name, 
							rka.Hive, 
							rka.ValueName);
					}
				}
			}
		}
	}
}