The most effiecient way is to directly access the DataSource. Here is some code that assumes you are using a DataTable as the DataSource. If you are using an IList, replace the DataRowView in the code below with the class type of the objects in your list.
CurrencyManager cm = grid.BindingContext[grid.DataSource, grid.Datamember] as CurrencyManager;
int rowIndex = -1;
for(int position = 0; position < cm.List.Count; ++position)
{
DataRowView drv = cm.List[position] as DataRowView;
if(drv["Col1''].Equals(25))
{
rowIndex = grid.Binder.PositionToRowIndex(position);
break;
}
}
//rowindex is the grid row index where Col1 has 25 in it.
