//创建撕裂检测界面
private void btn_Tear_Click(object sender, EventArgs e)
{
//判断子窗口是否有实例
if (tearFrm == null)
{
tearFrm = new TearFrm();
tearFrm.Show();
//子窗口关闭后增加释放实例的功能
tearFrm.FormClosing += ReleaseObjct_Tear;
}
else
{
//存在子窗口打开的时候，重新选择打开的子窗口
tearFrm.Activate();
}
}
//释放撕裂界面示例事件
private void ReleaseObjct_Tear(object sender, FormClosingEventArgs e)
{
//释放实例
tearFrm = null;
}
