/// <summary> /// 查看学生列表 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void tsmiStudentList_Click(object sender, EventArgs e) { StudentListForm studentListForm = StudentListForm.CreateInstance(); studentListForm.MdiParent = this; studentListForm.Show(); }
/// <summary> /// 创建实例 目的 使这个窗口只能被new一次 /// </summary> /// <returns></returns> public static StudentListForm CreateInstance() { if (studentListForm == null || studentListForm.IsDisposed)//判断是否为空和被释放 { studentListForm = new StudentListForm(); } return(studentListForm); }