"System.NullReferenceException" for Using Session in MVC

Question

In My MVC project, I am using session values like

var empId = Convert.ToInt32(Session["EmpId"].ToString());

I am getting Exception:

"An exception of type 'System.NullReferenceException' occurred in Project.Web.dll but was not handled in user code.

Additional information: Object reference not set to an instance of an object."

Have you checked Session["EmpId"] for null?

Gichamba
– Gichamba

2015-02-19 09:58:47 +00:00
Commented Feb 19, 2015 at 9:58 — Gichamba
– Gichamba, Commented Feb 19, 2015 at 9:58

Karthik Chintala · Accepted Answer · 2015-02-19 10:41:23Z

4

This error occurs when you call a method on the null object. In your case the value of Session["EmpId"] is NULL.

Which means you are calling NULL.ToString(), which is invaild hence it throws error.

You can avoid the error using null coaleascing operator or simply check null before performing any opearation on it.

Solution:

if(Session["EmpId"] == null)
 //do something
else
 var empId = Convert.ToInt32(Session["EmpId"].ToString());

Alternatively you can check my blog post on it

answered Feb 19, 2015 at 10:41

Karthik Chintala

5,5455 gold badges33 silver badges61 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Rob Over a year ago

I have the same issue but my property definition is like this get { if (Session["_exportViewModel1"] == null) Session["_exportViewModel1"] = new BG.Indigo.Controls.Utilities.CountrySurveyReportExportVM(); return (BG.Indigo.Controls.Utilities.CountrySurveyReportExportVM)Session["_exportViewModel1"]; } set { Session["_exportViewModel1"] = value; }

Ajay · Accepted Answer · 2015-02-19 10:07:32Z

1

Before use first check is it null or not.

var empId = Session["EmapId"] != null ? Convert.ToInt32(Session["EmapId"]) : 0;

answered Feb 19, 2015 at 10:07

Ajay

6,59818 gold badges83 silver badges135 bronze badges

Comments

Kartikeya Khosla · Accepted Answer · 2015-02-19 10:06:14Z

0

You have to check null as shown below :-

var empId = Convert.ToInt32((Session["EmpId"] ?? 0).ToString());

A more efficient way to accomplish your requirement :-

int temp = 0;
var empId = int.TryParse( Convert.ToString( Session["EmpId"] ),out temp );

edited Feb 19, 2015 at 10:06

answered Feb 19, 2015 at 10:00

Kartikeya Khosla

18.9k8 gold badges46 silver badges70 bronze badges

Collectives™ on Stack Overflow

"System.NullReferenceException" for Using Session in MVC

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related