Checking session if empty or not

Question

I want to check that session is null or empty i.e. some thing like this:

if(Session["emp_num"] != null) {     if (!string.IsNullOrEmpty(Session["emp_num"].ToString()))             {                 //The code             } } 

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Or just

 if(Session["emp_num"] != null)     {         // The code     } 

because sometimes when i check only with:

       if (!string.IsNullOrEmpty(Session["emp_num"].ToString()))                 {                     //The code                 } 

I face the following exception:

Null Reference exception

Answer 1

Use this if the session variable emp_num will store a string:

 if (!string.IsNullOrEmpty(Session["emp_num"] as string))  {                 //The code  } 

If it doesn't store a string, but some other type, you should just check for null before accessing the value, as in your second example.