Datatable's Compute Function For Rows

DataTable dt = WhateverCreatesDataTable();
DataRow dr = dt.Rows[0];
int sum = dt.Columns.Cast<DataColumn>().Sum(dc=>(int)dr[dc]);

DataTable dt = WhateverCreatesDataTable();
DataRow dr = dt.Rows[0];
int sum = 0;

foreach(DataColumn dc in dt.Columns)
  sum += (int)dr[dc];

DataColumn totalColumn = new DataColumn();
totalColumn.DataType = System.Type.GetType("System.Int32");
totalColumn.ColumnName = "Total";
totalColumn.Expression = "Product1 + Product2 + Product3 + Product4 + Product5";

// Populate and get the DataTable dt then add this computed column to this table

dt.Columns.Add(totalColumn);
//Now if you access the column "Total" of the table you will get the desired result.