C#实现自定义的窗口最大化、最小化和关闭按钮功能

using System;
using System.Drawing;
using System.Windows.Forms;

namespace CustomWindowButtons
{
    public partial class Form1 : Form
    {
        // 记录鼠标拖动时的起始位置
        private Point mouseDownPoint = Point.Empty;

        public Form1()
        {
            InitializeComponent();
            // 窗体初始化设置
            InitFormSettings();
            // 绑定按钮事件
            BindButtonEvents();
        }

        /// <summary>
        /// 初始化窗体设置（移除系统边框、设置窗体样式）
        /// </summary>
        private void InitFormSettings()
        {
            // 移除系统默认窗口边框和标题栏
            this.FormBorderStyle = FormBorderStyle.None;
            // 设置窗体默认大小
            this.Size = new Size(800, 600);
            // 居中显示
            this.StartPosition = FormStartPosition.CenterScreen;

            // 自定义按钮样式初始化（可选，简化外观）
            btnMin.Size = new Size(40, 30);
            btnMax.Size = new Size(40, 30);
            btnClose.Size = new Size(40, 30);
            btnMin.Text = "—";
            btnMax.Text = "□";
            btnClose.Text = "×";
            btnMin.Font = new Font("Arial", 12, FontStyle.Bold);
            btnMax.Font = new Font("Arial", 12, FontStyle.Bold);
            btnClose.Font = new Font("Arial", 12, FontStyle.Bold);

            // 排列按钮（窗体右上角）
            btnClose.Location = new Point(this.Width - 45, 5);
            btnMax.Location = new Point(this.Width - 90, 5);
            btnMin.Location = new Point(this.Width - 135, 5);
        }

        /// <summary>
        /// 绑定按钮的点击事件和鼠标悬浮/离开事件
        /// </summary>
        private void BindButtonEvents()
        {
            // 最小化按钮点击事件
            btnMin.Click += BtnMin_Click;
            // 最大化/还原按钮点击事件
            btnMax.Click += BtnMax_Click;
            // 关闭按钮点击事件
            btnClose.Click += BtnClose_Click;

            // 可选：添加按钮鼠标悬浮效果，提升交互体验
            btnMin.MouseEnter += Button_MouseEnter;
            btnMax.MouseEnter += Button_MouseEnter;
            btnClose.MouseEnter += Button_MouseEnter;
            btnMin.MouseLeave += Button_MouseLeave;
            btnMax.MouseLeave += Button_MouseLeave;
            btnClose.MouseLeave += Button_MouseLeave;
        }

        #region 按钮事件处理
        /// <summary>
        /// 最小化按钮点击事件
        /// </summary>
        private void BtnMin_Click(object sender, EventArgs e)
        {
            // 调用窗体内置方法，将窗口最小化到任务栏
            this.WindowState = FormWindowState.Minimized;
        }

        /// <summary>
        /// 最大化/还原按钮点击事件
        /// </summary>
        private void BtnMax_Click(object sender, EventArgs e)
        {
            // 判断当前窗口状态，切换最大化/还原
            if (this.WindowState == FormWindowState.Maximized)
            {
                // 还原窗口默认大小
                this.WindowState = FormWindowState.Normal;
                btnMax.Text = "□"; // 更新按钮文本
            }
            else
            {
                // 最大化窗口
                this.WindowState = FormWindowState.Maximized;
                btnMax.Text = "■"; // 更新按钮文本
            }

            // 窗口状态变化后，重新调整按钮位置（避免最大化后按钮偏移）
            AdjustButtonPosition();
        }

        /// <summary>
        /// 关闭按钮点击事件
        /// </summary>
        private void BtnClose_Click(object sender, EventArgs e)
        {
            // 调用窗体内置方法，关闭当前窗体
            this.Close();
        }

        /// <summary>
        /// 鼠标悬浮按钮时，更改按钮背景色
        /// </summary>
        private void Button_MouseEnter(object sender, EventArgs e)
        {
            Button btn = sender as Button;
            if (btn != null)
            {
                // 关闭按钮悬浮时设置红色背景，其他按钮设置浅灰色
                btn.BackColor = btn == btnClose ? Color.LightCoral : Color.LightGray;
            }
        }

        /// <summary>
        /// 鼠标离开按钮时，恢复按钮默认背景色
        /// </summary>
        private void Button_MouseLeave(object sender, EventArgs e)
        {
            Button btn = sender as Button;
            if (btn != null)
            {
                btn.BackColor = SystemColors.Control;
            }
        }
        #endregion

        #region 辅助方法
        /// <summary>
        /// 调整按钮位置（适配窗口最大化/还原状态）
        /// </summary>
        private void AdjustButtonPosition()
        {
            btnClose.Location = new Point(this.Width - 45, 5);
            btnMax.Location = new Point(this.Width - 90, 5);
            btnMin.Location = new Point(this.Width - 135, 5);
        }

        /// <summary>
        /// 实现窗体拖动功能（重写鼠标按下/移动/松开事件）
        /// </summary>
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            // 记录鼠标按下时的坐标（相对于窗体）
            if (e.Button == MouseButtons.Left)
            {
                mouseDownPoint = new Point(e.X, e.Y);
            }
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);
            // 鼠标左键按住且起始位置有效时，拖动窗体
            if (e.Button == MouseButtons.Left && mouseDownPoint != Point.Empty)
            {
                // 计算窗体新位置
                this.Location = new Point(
                    this.Left + (e.X - mouseDownPoint.X),
                    this.Top + (e.Y - mouseDownPoint.Y)
                );
            }
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            // 鼠标松开后，重置起始位置
            mouseDownPoint = Point.Empty;
        }
        #endregion

        /// <summary>
        /// 窗口大小改变时，重新调整按钮位置（适配手动拉伸窗口）
        /// </summary>
        protected override void OnResize(EventArgs e)
        {
            base.OnResize(e);
            if (this.WindowState != FormWindowState.Minimized)
            {
                AdjustButtonPosition();
            }
        }
    }
}