DataTable转Json

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