C#最大化和最小化启动窗体

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

using System.Runtime.InteropServices;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
         
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
        }
        private const int SW_HIDE = 0;
        private const int SW_SHOWNORMAL = 1;
        private const int SW_SHOWMINIMIZED = 2;
        private const int SW_SHOWMAXIMIZED = 3;
        private const int SW_SHOWNOACTIVATE = 4;
        private const int SW_RESTORE = 9;
        private const int SW_SHOWDEFAULT = 10;

        [DllImport("user32.dll")]
        private static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);

        private void button1_Click(object sender, EventArgs e)
        {//最小化显示窗体
            ShowWindowAsync(this.Handle, SW_SHOWMINIMIZED);
        }
        private void button2_Click(object sender, EventArgs e)
        {//最大化显示窗体
            ShowWindowAsync(this.Handle, SW_SHOWMAXIMIZED);
        }
        private void button3_Click(object sender, EventArgs e)
        {//还原显示窗体
            ShowWindowAsync(this.Handle, SW_RESTORE);
        }
    }
}