void ComboBox_SelectedValueChanged(object sender, EventArgs e)
        {
            //      int idx = Convert.ToInt32(m_CurrentNode.m_ComboBox.SelectedValue);
            //      List<Attribute_Db_Table_Field> lstAttribute_Db_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldList();
            //      Attribute_Db_Table_Field objAttribute_Db_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldObjectGivenId(idx, lstAttribute_Db_Table_Field);
            //      List<LogicalTreeData> lstLogicalTreeData = Attribute_Db_Table_Field_BL.GenerateAndExecuteQuery(objAttribute_Db_Table_Field);
            ////      this.SelectedNode = m_CurrentNode;

            //      foreach (LogicalTreeData i in lstLogicalTreeData)
            //      {
            //         switch (m_CurrentNode.NodeType)
            //         {
            //            case NodeType.RootNode:
            //               LogicalTreeNode n = new LogicalTreeNode(i.Desc);
            //               n.NodeType = NodeType.PassThroughNode;
            //               this.m_CurrentNode.Nodes.Add(n);
            //               break;
            //            case NodeType.PassThroughNode:
            //               break;
            //            case NodeType.TerminalNode:
            //               break;
            //         }
            //      }


            int idx = Convert.ToInt32(m_CurrentNode.m_ComboBox.SelectedValue);
            //        List<Attribute_Db_Table_Field> lstAttribute_Db_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldList();
            Attribute_Db_Table_Field objAttribute_Db_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldObjectGivenId(idx, lstAttribute_Db_Table_Field);
            List <LogicalTreeData>   lstLogicalTreeData          = Attribute_Db_Table_Field_BL.GenerateAndExecuteQuery(objAttribute_Db_Table_Field);

            // mch.  01.04.2018.  commented out line below.
            //   this.SelectedNode = m_CurrentNode;
            // mch.  This is, I think, where I am having problems with creating child node for root node.
            // mch.  I think what i need to do here is create the ...
            //     n.Nodes.Add()

            foreach (LogicalTreeData i in lstLogicalTreeData)
            {
                switch (m_CurrentNode.NodeType)
                {
                case NodeType.RootNode:
                    LogicalTreeNode c = new LogicalTreeNode(i.Desc);

                    c.NodeType = NodeType.PassThroughNode;
                    // mch.  01.04.2018.  changed from m_CurrentNode to n
                    this.n.Nodes.Add(c);
                    break;

                case NodeType.PassThroughNode:
                    break;

                case NodeType.TerminalNode:
                    break;
                }
            }
            HideComboBox();
        }
        private LogicalTreeNode n; // mch.  01.04.2018.  Moved n out from local variable

        public LogicalTreeView()
        {
            //List<Attribute_Db_Table_Field> lstAttribute_Table_Field = new List<Attribute_Db_Table_Field>();
            //lstAttribute_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldList();
            //String tmpStr = ((lstAttribute_Table_Field[0].Attribute_Db).Trim('[')).Trim(']');
            //LogicalTreeNode n = new LogicalTreeNode(tmpStr);
            //this.Nodes.Add(n);

            //  lstAttribute_Table_Field = new List<Attribute_Db_Table_Field>();
            // lstAttribute_Table_Field
            lstAttribute_Db_Table_Field = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldList();

            // mch.  01.06.2018.  Added line below.
            lstAttribute = Attribute_BL.GetAttributeList();

            // mch.  01.09.2018.  Test start


            // Attribute_Db_Table_Field obj;

            //     obj = new Attribute_Db_Table_Field();


            List <Attribute_Db_Table_Field> lstAttr;
            Attribute_Db_Table_Field        obj;

            lstAttr = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldList();


            //    Attribute_Db_Table_Field obj = (Attribute_Db_Table_Field) from att in lstAttribute where att.Attribute_Name == "Period" select att;

            obj = Attribute_Db_Table_Field_BL.GetAttributeDbTableFieldObjectGivenId(5, lstAttr);


            string sqlString = LogicalTreeData_BL.ConstructQueryString(obj);

            // mch.  01.09.2018.  End start

            // lstAttribute_Table_Field
            String tmpStr = ((lstAttribute_Db_Table_Field[0].Attribute_Db).Trim('[')).Trim(']');

            // lstAttribute_Table_Field
            n          = new LogicalTreeNode(tmpStr, lstAttribute, lstAttribute_Db_Table_Field);
            n.NodeType = NodeType.RootNode;



            this.Nodes.Add(n);
        }