窗口渐变

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

namespace SplashScreen
{
    public partial class SplashScreen : Form
    {
        public SplashScreen()
        {
            InitializeComponent();
        }
        private bool isFade = true;

        private void SplashScreen_Load(object sender, EventArgs e)
        {
            this.ClientSize = this.BackgroundImage.Size;

            this.Opacity = 0;

            this.timer1.Interval = 100;

            this.timer1.Enabled = true;

            this.timer1.Start();

        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (isFade)
            {
                this.Opacity += 0.01;//当透明变为不透明

                if (this.Opacity >= 1)//当完全不透明时再由不透明变为透明
                {
                    this.timer1.Stop();
                    isFade = false;
                }
            }
            else
            {
                this.Opacity -= 0.01;//由不透明变为透明

                if (this.Opacity <= 0)//当完全透明时停止计时器，并退出欢迎界面。
                {
                    this.timer1.Stop();
                    this.Close();
                }
            }

        }
    }
}