Как определить какой объект находится под курсором мыши?

private void MyEventHandler_MouseUp(object sender, arguments e)
{
    MessageBox.Show((sender as Button).Name);
}

            this.pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox_MouseDown);
            this.pictureBox1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pictureBox_MouseUp);
            this.pictureBox3.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox_MouseDown);
            this.pictureBox3.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pictureBox_MouseUp);
            this.pictureBox1.MouseEnter += new System.EventHandler(this.pictureBox_MouseEnter);
            this.pictureBox3.MouseEnter += new System.EventHandler(this.pictureBox_MouseEnter);

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        Boolean imageCapture = false;
        Boolean imageLeave = false;
        PictureBox _sender;
        private void pictureBox_MouseDown(object sender, MouseEventArgs e)
        {
            _sender = (sender as PictureBox);
            imageCapture = true;
        }
        private void pictureBox2_MouseEnter(object sender, EventArgs e)
        {
            if (imageLeave)
            {
                imageLeave = false;
 
                ////////////////К примеру помещаем во второй картинку из первого PictureBox
                pictureBox2.Image = _sender.Image;
            }
        }
        private void pictureBox_MouseUp(object sender, MouseEventArgs e)
        {
            if (imageCapture) imageLeave = true;
            imageCapture = false;
        }
        private void Form1_MouseEnter(object sender, EventArgs e)
        {
            imageLeave = false;
        }
 
        private void pictureBox_MouseEnter(object sender, EventArgs e)
        {
            imageLeave = false;
        }
    }
}