How to pass set Crystal Report Parameter value from asp.net c# in runtime

When you design a crystal report most of the time you need to use crstal report parameter specially to design report header. Like you are going to ouptut a report which contains a ceratin date data or may date range data. SO that you need to write the date range or date to specify the report data date. In this scenario you need to use Crystal report parameter because the data you will bind, may