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question regarding request.querystring

Posted By:      Posted Date: August 25, 2010    Points: 0   Category :ASP.Net

I have a url like this:

http://www.somepage.com/main.aspx.  In this page, when I click on a link it takes me to a page http://www.somepage.com/cental.aspx?cid=200.  So in the cental.aspx.cs page I did the following in the page load:


if(request.querystring["comp"].tostring() != null)


//do some thing


So I got an error like: object reference not set to an instance of reference.


My problem is, I am using the same page.  So when I go from some page, I will have "comp".  but other times not.  So when there is no "comp", how do I handle it in request.querystring?


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