Take a look at below code:
DataSet ds = new DataSet();
foreach(DataTable origDt in origDataSet)
{
DataTable encodedDt = origDt.Clone();
for(int i=0; i<origDt.Rows.Count; i++)
{
DataRow dr = origDt.Rows[i];
encodedDt.ImportRow(HttpEncode(dr));
}
ds.Tables.Add(encodedDt);
}