C#窗体淡入淡出

//淡入
public int state = 0;private void f2_Load(object sender, EventArgs e)
{this.Opacity = 0;
} private void timer1_Tick(object sender, EventArgs e)
{if (state == 0)
{this.Opacity += 0.02;if (this.Opacity == 1)
{
state = 1;
timer1.Enabled = false;
}
}else
{this.Opacity = Opacity - 0.02;if (this.Opacity == 0)
{
Application.ExitThread();
}
}
}//退出
private void f2closing(object sender, FormClosingEventArgs e)
{
e.Cancel = true;
timer1.Start();
}