How to check that Request.QueryString has a specific value or not in ASP.NET?

Question

I have an error.aspx page. If a user comes to that page then it will fetch the error path in page_load() method URL using Request.QueryStrin

Answer 1

think the check you're looking for is this:

if(Request.QueryString["query"] != null) 

It returns null because in that query string it has no value for that key.