Question

I want to know the exact row number and I’m using this code

DataRow[] resultsize = dt.Select("psize like '%" + hdncurrentsize.Value + "%'");

but result is always 1 but not the exact matching row number.

Answer 1

If you are interested in knowing the row position,You can try this

DataRow[] resultsize = dt.Select("psize like '%" + hdncurrentsize.Value + "%'");

foreach(var row in resultsize){    
   var idx = dt.Rows.IndexOf<DataRow>(row);    
}

Or

DataRow[] allRows;    
dt.Rows.CopyTo(allRows,0);

foreach(var row in resultsize){    
   var idx = Array.FindIndex<DataRow>
                   (allRows, (item) => { return item == row; });
}