Object reference not set in asp.net

Question

if (Session["admin_uname"].ToString() == "")
{
    Response.Redirect("login.aspx");
}
else
{
    string userid = Session["admin_uname"].ToString(); 

}

i have wrote above code for sessions... but problem is if there is any session variable it was working properly

if session is not there it was not redirecting to login page and giving an error like

OBJECT REFERENCE NOT SET.

Almost all cases of `NullReferenceException` are the same. Please see "[What is a NullReferenceException in .NET?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-in-net)" for some hints. — John Saunders, Aug 11 '13 at 19:32

score 2 · Answer 1 · answered Aug 11 '13 at 18:37

If there is no session exits then u will not able to compare anything. So check its Null or Not. This is how u check the session.

   if (Session["admin_uname"] == null)
    {
        Response.Redirect("login.aspx");
    }
    else
    {
        string userid = Session["admin_uname"].ToString(); 
    }

score 0 · Answer 2 · answered Aug 11 '13 at 18:38

0

When you call ToString() on that null, you get the exception. So check for Null value too. You can try this:-

if (Session["admin_uname"].ToString() == "" || Session["admin_uname"].ToString() == Null)

answered Aug 11 '13 at 18:38

Rahul Tripathi

168,305
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score 0 · Answer 3 · answered Aug 11 '13 at 18:39

0

Check for nullity before you reference the object, like

if (Session["admin_uname"] != null)

// do something

answered Aug 11 '13 at 18:39

Rahul

76,197
13
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125

score 0 · Answer 4 · edited May 21 '14 at 14:42

0

You could use this:

if (String.IsNullOrEmpty(Session["admin_uname"].ToString()))
{
    Response.Redirect("login.aspx");
}
else
{
    string userid = Session["admin_uname"].ToString(); 
}

edited May 21 '14 at 14:42

Ashley Medway

7,151
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answered Aug 11 '13 at 18:43

Goran Štuc

581
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15

score 0 · Answer 5 · answered Aug 11 '13 at 19:19

0

I would do like this:

if (Session["admin_uname"] != null || Session["admin_uname"].ToString() == "")
    Response.Redirect("login.aspx");

string userid = Session["admin_uname"].ToString();

answered Aug 11 '13 at 19:19

afzalulh

7,925
2
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score 0 · Answer 6 · answered Aug 11 '13 at 19:41

0

One more entry:

string userid = Session["admin_uname"] ?? "";
if (string.IsNullOrEmpty(userid))
{
    Response.Redirect("login.aspx");
}

answered Aug 11 '13 at 19:41

Joel Coehoorn

399,467
113
570
794

Object reference not set in asp.net

6 Answers6