如何确定MDI子窗体的屏幕位置?

您必须使用父级的MDI客户机窗口的pointToScreen()方法:

    private void button1_Click(object sender, EventArgs e) {
        if (this.MdiParent != null) {
            MdiClient client = null;
            foreach (Control ctl in this.MdiParent.Controls) {
                if (ctl is MdiClient) { client = ctl as MdiClient; break; }
            }
            this.WindowState = FormWindowState.Normal;
            Point loc = client.PointToScreen(this.Location);
            this.MdiParent = null;
            this.Location = loc;
        }
    }

你无法避免在Aero上得到的轻微偏移,也无法避免闪烁。