运行时通过拖拽动态改变控件的大小 Virus

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication11
{
    public partial class Form1 : Form
    {
        private int oldx;
        private int oldy;

        enum mPosition
        {
            left,
            right,
            top,
            bottom
        }
        private mPosition adjust;
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_MouseDown(object sender, MouseEventArgs e)
        {
            oldx = e.X;
            oldy = e.Y;
        }

        private void button1_MouseMove(object sender, MouseEventArgs e)
        {
            Rectangle rectLeft = new Rectangle(0, 2, 2, button1.Height - 4);
            Rectangle rectRight = new Rectangle(button1.Width - 2, 2, 2, button1.Width);
            Rectangle rectTop = new Rectangle(2, 0, button1.Width - 4, 2);
            Rectangle rectBottom = new Rectangle(2, button1.Height - 2, button1.Width - 4, 2);

            if (rectLeft.Contains(e.X, e.Y))
            {
                adjust = mPosition.left;
                button1.Cursor = Cursors.SizeWE;

            }
            else if (rectRight.Contains(e.X, e.Y))
            {
                adjust = mPosition.right;
                button1.Cursor = Cursors.SizeWE;
            }
            else if (rectTop.Contains(e.X, e.Y))
            {
                adjust = mPosition.top;
                button1.Cursor = Cursors.SizeNS;
            }
            else if (rectBottom.Contains(e.X, e.Y))
            {
                adjust = mPosition.bottom;
                button1.Cursor = Cursors.SizeNS;
            }
            else
            {
                button1.Cursor = Cursors.Default;
            }
        }

        private void button1_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                int dx = e.X - oldx;
                int dy = e.Y - oldy;
                switch (adjust)
                {
                    case mPosition.left:
                        button1.Left += dx;
                        button1.Width -= dy;
                        break;
                    case mPosition.right:
                        button1.Width += dx;
                        break;
                    case mPosition.top:
                        button1.Top += dy;
                        button1.Height -= dy;
                        break;
                    case mPosition.bottom:
                        button1.Height += dy;
                        break;

                }
            }

        }


    }
}