private string DataTable2Json(DataTable dt)
    ...{
        StringBuilder jsonBuilder = new StringBuilder();
        jsonBuilder.Append("{/"");
        jsonBuilder.Append(dt.TableName);
        jsonBuilder.Append("/":[");
        for (int i = 0; i < dt.Rows.Count; i++)
        ...{
            jsonBuilder.Append("{");
            for (int j = 0; j < dt.Columns.Count; j++)
            ...{
                jsonBuilder.Append("/"");
                jsonBuilder.Append(dt.Columns[j].ColumnName);
                jsonBuilder.Append("/":/"");
                jsonBuilder.Append(dt.Rows[i][j].ToString());
                jsonBuilder.Append("/",");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            jsonBuilder.Append("},");
        }
        jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
        jsonBuilder.Append("]");
        jsonBuilder.Append("}");
        return jsonBuilder.ToString();
    }