类似qq弹窗，自动消失

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FormCPM
{
    public partial class Form1 : Form
    {
        const int countDown = 60;//倒计时
        int currCountDown = countDown;//倒计时
        bool isCount = true;
        Thread thread;
        public Form1()
        {
            InitializeComponent();
            thread = new Thread(() =>
            {
                while (true)
                {
                    if (isCount)
                    {
                        if (currCountDown <= 0)
                        {
                            this.Invoke(new Action(() =>
                            {
                                this.Close();
                            }));
                            break;
                        }
                        else
                        {
                            Thread.Sleep(100);
                            currCountDown--;
                            this.Invoke(new Action(() =>
                            {
                                this.Opacity = this.Opacity - this.Opacity / countDown;
                            }));

                        }
                    }
                    else
                    {
                        Thread.Sleep(10);
                    }
                }
            });
            thread.IsBackground = true;
        }
        [DllImport("user32")]

        private static extern bool AnimateWindow(IntPtr hwnd, int dwTime, int dwFlags);



        //下面是可用的常量,按照不合的动画结果声明本身须要的

        private const int AW_HOR_POSITIVE = 0x0001;//自左向右显示窗口,该标记可以在迁移转变动画和滑动动画中应用。应用AW_CENTER标记时忽视该标记

        private const int AW_HOR_NEGATIVE = 0x0002;//自右向左显示窗口,该标记可以在迁移转变动画和滑动动画中应用。应用AW_CENTER标记时忽视该标记

        private const int AW_VER_POSITIVE = 0x0004;//自顶向下显示窗口,该标记可以在迁移转变动画和滑动动画中应用。应用AW_CENTER标记时忽视该标记

        private const int AW_VER_NEGATIVE = 0x0008;//自下向上显示窗口,该标记可以在迁移转变动画和滑动动画中应用。应用AW_CENTER标记时忽视该标记该标记

        private const int AW_CENTER = 0x0010;//若应用了AW_HIDE标记,则使窗口向内重叠;不然向外扩大

        private const int AW_HIDE = 0x10000;//隐蔽窗口

        private const int AW_ACTIVE = 0x20000;//激活窗口,在应用了AW_HIDE标记后不要应用这个标记

        private const int AW_SLIDE = 0x40000;//应用滑动类型动画结果,默认为迁移转变动画类型,当应用AW_CENTER标记时,这个标记就被忽视

        private const int AW_BLEND = 0x80000;//应用淡入淡出结果



        private void Form1_Load(object sender, EventArgs e)
        {

            int x = Screen.PrimaryScreen.WorkingArea.Right - this.Width;

            int y = Screen.PrimaryScreen.WorkingArea.Bottom - this.Height;

            this.Location = new Point(x, y);//设置窗体在屏幕右下角显示

            AnimateWindow(this.Handle, 1000, AW_SLIDE | AW_ACTIVE | AW_VER_NEGATIVE);
            thread.Start();

        }private void Form1_MouseEnter(object sender, EventArgs e)
        {
            isCount = false;
            currCountDown = countDown;
            this.Opacity = 1d;
        }

        private void Form1_MouseLeave(object sender, EventArgs e)
        {
            isCount = true;
        }

    }
}