How to validate data table(datas) in data set?

Question

i have one dataset and multiple(like 4 or 5 tables) datatable(with different rows and columns count). In this data table i have some mandatory field to validate.<br /> 1.item number (itemnumber:12)(itemnumber is description it is in any row and the value of item number(12) is next same row and next column of the description)<br /> 2.manufacturer name<br /> 3.rev number.<br /><div> now i want to validate the in this manner how to do it.</div><div>&nbsp;</div><div><strong>What I have tried:</strong><br /> <br /> I used <br /> if (ds.Tables[i].Rows[12][25].ToString() == "")<br /> {<br /> dt.Rows.Add();<br /> dt.Rows[mn][0] = "Item number Should be mandatory";<br /> <br /> }<br /> in this code particular field is empty to add the message to one table and show.but the column and row values are changed. </div>