How to detect a session and a request.querystring is Null?

[legendgod]

Hi guys, thank you for reading.

 

I have a page which have a function to request.querystring("sth") the previous page's form. However, due to the program logic, sometimes the previous page do not give out any querystring. Therefore, if I go on the request.querystring("sth"), a nullreference error occur. Is there any method to know request.querystring("sth") is null or not?

 

Also, the same problem also occur for the session. I don't know if there are any method to know Session("sth") is null or not.

 

Thanks.

[wessamzeidan]

I always use

 

If Request.QueryString("myvar")<>"" Then

 

'''code

 

End If

 

works for session variables too

[legendgod]

Thanks for your suggestion. It is easier than I think. =D