Enforces null columns to prevent getting dropped when serializing

dataTableEnforceNulls.cs

       private static void datatableEnforceNulls(DataTable resultTable)
        {

            List<string> removeList = new List<string>();

            foreach (DataColumn column in resultTable.Columns)
            {

                if (resultTable.Rows.OfType<DataRow>().All(r => r.IsNull(column)))
                {
                    if (column.DataType != typeof(String))
                    {
                        removeList.Add(column.ColumnName);
                    }
                    if (column.DataType == typeof(String))
                    {
                        column.DefaultValue = "";
                    }
                }
            }
            foreach (string col2Remove in removeList)
            {
                resultTable.Columns.Remove(col2Remove);
                resultTable.Columns.Add(col2Remove);
                resultTable.Columns[col2Remove].DefaultValue = "";
            }

            int i, j;
            for (i = 0; i < resultTable.Columns.Count; i++)
            {
                for (j = 0; j < resultTable.Rows.Count; j++)
                {
                    if (resultTable.Columns[i].DataType.ToString() == "System.String")
                    {
                        if (resultTable.Rows[j][i] == DBNull.Value || resultTable.Rows[j][i].ToString().Trim() == "")
                            resultTable.Rows[j][i] = "";
                    }
                }
            }
        }