Json转换类库

        private string DtConvertJson(DataTable dt , string modelName="")
        {
            int colNum = dt.Columns.Count;
            int rowNum = dt.Rows.Count;
            StringBuilder sb = new StringBuilder();

            if(rowNum > 1)  sb.Append("{\""+ modelName +"\":" + "[");

            for (int i = 0; i < rowNum; i++) {
                sb.Append("{");

                for(int k = 0; k < colNum; k++)
                {
                    sb.Append("\"" + dt.Columns[k].ColumnName + "\":\"" + dt.Rows[i][k] +"\"");
                    if (k < colNum - 1) sb.Append(",");
                }

                sb.Append("}");
                if (i < rowNum - 1) sb.Append(",");
            };
            if (rowNum > 1) sb.Append("]}");

            return sb.ToString();
        }