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);}}