Winform 去掉 最大化 最小化 关闭按钮（不是关闭按钮变灰）终极解决办法

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;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;

namespace WinDemo
{
    public partial class Form5 : Form
    {
        public Form5()
        {
            InitializeComponent();
        }

        /// <summary>
        /// Button 按钮重绘事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Paint(object sender, PaintEventArgs e)
        {
            GraphicsPath myPath = new GraphicsPath();
            Rectangle rect = new Rectangle(0,0,574,362);//后面2个数据调整窗体大小
            myPath.AddRectangle(rect);
            this.Region = new Region(myPath);
        }

        [DllImport("user32.dll")]
        static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);

        [DllImport("User32.dll")]

        private static extern IntPtr GetWindowDC(IntPtr hWnd);

        protected override void WndProc(ref System.Windows.Forms.Message m)
        {
            const int WM_NCPAINT = 0x85;
            base.WndProc(ref m);

            if (m.Msg == WM_NCPAINT)
            {

                IntPtr hdc = GetWindowDC(m.HWnd);
                if ((int)hdc != 0)
                {
                    Graphics g = Graphics.FromHdc(hdc);
                    Pen pen1 = new Pen(Color.FromArgb(64,64,64));
                    Pen pen2 = new Pen(Color.FromArgb(128, 128, 128));
                    Pen pen3 = new Pen(Color.FromArgb(212, 208, 200));
                    g.DrawLine(pen1, 573, 0, 573, 360);//最外边
                    g.DrawLine(pen2, 572, 1, 572, 359);//最外边第二条白色
                    g.DrawLine(pen3, 571, 2, 571, 359);
                    g.DrawLine(pen3, 571, 2, 571, 359);
                    g.Flush();
                    ReleaseDC(m.HWnd, hdc);
                }
            }
        }
        private void Form5_MouseCaptureChanged(object sender, EventArgs e)
        {
            Graphics g = this.CreateGraphics();
            Pen pen1 = new Pen(Color.FromArgb(64, 64, 64));
            Pen pen2 = new Pen(Color.FromArgb(128, 128, 128));
            Pen pen3 = new Pen(Color.FromArgb(212, 208, 200));
            g.DrawLine(pen1, 573, 0, 573, 360);//最外边
            g.DrawLine(pen2, 572, 1, 572, 359);//最外边第二条白色
            g.DrawLine(pen3, 571, 2, 571, 359);
            g.DrawLine(pen3, 571, 2, 571, 359);
            g.Flush();
        }
}
}

using System.Runtime.InteropServices;

        [DllImport("user32.dll")]
        internal static extern IntPtr GetSystemMenu(IntPtr hwnd, bool bRevert);

        [DllImport("user32.dll")]
        internal static extern int GetMenuItemCount(IntPtr hMenu);

        [DllImport("user32.dll")]
        internal static extern int RemoveMenu(IntPtr hMenu, int uPosition, int uFlags);

        ///   <summary> 
        ///   窗体的关闭按钮失效 
        ///   </summary> 
        protected void CloseButtonEnable()
        {
            //   默认窗口去除关闭按钮 
            const int MF_BYPOSITION = 0x00000400;

            IntPtr hWindow = this.Handle;
            IntPtr hMenu = GetSystemMenu(hWindow, false);
            int count = GetMenuItemCount(hMenu);
            RemoveMenu(hMenu, count - 1, MF_BYPOSITION);
            RemoveMenu(hMenu, count - 2, MF_BYPOSITION);
        }

        private void confirm_Load(object sender, EventArgs e)
        {
            CloseButtonEnable();

        }