GtkSharp/glib/SignalCallback.cs

// GtkSharp.SignalCallback.cs - Signal callback base class implementation
//
// Authors: Mike Kestner <mkestner@speakeasy.net>
//
// (c) 2001 Mike Kestner

namespace GtkSharp {
	using System;
	using System.Collections;
	using System.Runtime.InteropServices;
	using GLib;

	/// <summary>
	///	SignalCallback Class
	/// </summary>
	///
	/// <remarks>
	///	Base Class for GSignal to C# event marshalling.
	/// </remarks>

	public abstract class SignalCallback {

		// A counter used to produce unique keys for instances.
		protected static int _NextKey = 0;

		// Hashtable containing refs to all current instances.
		protected static Hashtable _Instances = new Hashtable ();

		// protected instance members
		protected GLib.Object _obj;
		protected EventHandler _handler;
		protected int _key;

		/// <summary>
		///	SignalCallback Constructor
		/// </summary>
		///
		/// <remarks>
		///	Initializes instance data.
		/// </remarks>

		public SignalCallback (GLib.Object obj, IntPtr raw,
				     String name, EventHandler eh)
		{
			_key = _NextKey++;
			_obj = obj;
			_handler = eh;
			_Instances [_key] = this;
		}

		// Destructor needed to release references from the instance
		// table and unpin the delegate if no refs remain.
		~SignalCallback ()
		{
			_Instances.Remove (_key);
		}
	}
}