winfrom-窗体打开大小和全屏设置

窗体打开满屏（非最大化），点击按钮全屏，ESC键按下时推出全屏：

public Form1()
{
InitializeComponent();

KeyPreview = true;
DoubleBuffered = true;
StartPosition = FormStartPosition.Manual; //窗体的位置由 Forms.Control.Location 属性确定。

Rectangle rect = Screen.GetWorkingArea(this);
this.Width = rect.Width;
this.Height = rect.Height;
}

private void fullscreen_Click(object sender, EventArgs e)
{
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
switch (e.KeyCode)
{
case Keys.Escape:
returnback();
break;

default:
break;
}
}
private void returnback()
{
this.WindowState = FormWindowState.Normal;
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Sizable;
}