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();
            }
        }
    }
}