Convert DataTable/DataSet to Json string

public string GetJson(DataSet ds)
    {
        System.Web.Script.Serialization.JavaScriptSerializer serializer = new

        System.Web.Script.Serialization.JavaScriptSerializer();
        List<object> rowss = new List<object>();
        List<Dictionary<string, object>> rows =
          new List<Dictionary<string, object>>();
        Dictionary<string, object> row = null;
        foreach (DataTable dt in ds.Tables)
        {
            rows = new List<Dictionary<string, object>>();
            foreach (DataRow dr in dt.Rows)
            {
                row = new Dictionary<string, object>();
                foreach (DataColumn col in dt.Columns)
                {
                    row.Add(col.ColumnName.Trim(), dr[col]);
                }
                rows.Add(row);
            }
            rowss.Add(rows);
        }
        return serializer.Serialize(rowss);
    }

 public string GetJson(DataTable dt)

    {
        System.Web.Script.Serialization.JavaScriptSerializer serializer = new

        System.Web.Script.Serialization.JavaScriptSerializer();
        List<Dictionary<string, object>> rows =
          new List<Dictionary<string, object>>();
        Dictionary<string, object> row = null;

        foreach (DataRow dr in dt.Rows)
        {
            row = new Dictionary<string, object>();
            foreach (DataColumn col in dt.Columns)
            {
                row.Add(col.ColumnName.Trim(), dr[col]);
            }
            rows.Add(row);
        }
        return serializer.Serialize(rows);
    }