/// <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);
}