使用上下左右和回车切换窗体上的控件焦点

        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyData == Keys.Right || e.KeyData == Keys.Down || e.KeyData == Keys.Enter)
            { // 焦点向后移动

                this.SelectNextControl(this.ActiveControl, true, true, false, true);
            }

            if (e.KeyData == Keys.Left || e.KeyData == Keys.Up)
            { // 焦点向前移动

                this.SelectNextControl(this.ActiveControl, false, true, false, true);
            }
        }