private void button_BackReturnBook_Click(object sender, EventArgs e)//点击返回还书界面按钮事件
{
this.Close();
frm_ReturnBook returnbook = new frm_ReturnBook();
returnbook.Show();
}
private void button_ReturnBook_Click(object sender, EventArgs e)
{
frm_ReturnBook ReturnBook = new frm_ReturnBook();//还书窗体
ReturnBook.Show();
}