public DataModelTableColumn Column(string columnName)
 {
     DataModelTableColumn column = null;
     if (columns.TryGetValue(columnName, out column)) return column;
     column = new DataModelTableColumn(columnName);
     columns[columnName] = column;
     return column;
 }
        public DataModelTableColumn Column(string columnName)
        {
            DataModelTableColumn column = null;

            if (columns.TryGetValue(columnName, out column))
            {
                return(column);
            }
            column = new DataModelTableColumn(columnName);
            columns[columnName] = column;
            return(column);
        }