Conversion Error:Input string was not in correct format

Question

HI
 This is my code
 paramCol[2] = new SqlParameter("@SalesWeek", SqlDbType.TinyInt);
 paramCol[2].Value =Convert.ToByte(lblSalesWeek.Text.Trim());

In my Storedprocedure Sakesweek datatype is Tiny int
so when i convert getting error like input string was not in correct format
plz help me how to convert this code