how to search datatable value by using tetbox by loops

Question

 i tried fallowing 

any

am unable how to generate loops to comparision datatable 

 

string searchExpression = SearchBox.Text;

DataRow[] foundrows = dt.Select(searchExpression);

dt.DefaultView.RowFilter = searchExpression;

dt.DefaultView.RowFilter = string.Format("[{0}] LIKE '%{1}%'", searchExpression);