DevExpress.Utils.ToolTipLocation

  private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if ((sender as TextBox).Text.Length == 0)
            {
                DevExpress.Utils.ToolTipLocation tipLocation = new DevExpress.Utils.ToolTipLocation();
                toolTipController1.ShowHint("不能为空", textBox1, ToolTipLocation.RightCenter);

            }

        }