Object reference not set to an instance of an object.

Question

3.50/5 (2 votes)

See more:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using DevExpress;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void ASPxButton1_Click(object sender, EventArgs e)
    {
        Response.Cookies.Add(new HttpCookie("MyCookie", ASPxTextBox2.Text));
    }
    protected void ASPxButton2_Click(object sender, EventArgs e)
    {
        Session["Mysession"] = ASPxTextBox3.Text;
    }
    protected void ASPxButton3_Click(object sender, EventArgs e)
    {
        ViewState.Add("MyViewState",ASPxTextBox4.Text);
    }
    protected void ASPxButton4_Click(object sender, EventArgs e)
    {
        ASPxLabel1.Text = Server.HtmlEncode(Request.Cookies["Mycookie"].Value);
        ASPxLabel2.Text = Session["Mysession"].ToString();
        ASPxLabel3.Text = ViewState["MyViewState"].ToString();
    }
}

error...

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 29: ASPxLabel1.Text = Server.HtmlEncode(Request.Cookies["Mycookie"].Value);
Line 30: ASPxLabel2.Text = Session["Mysession"].ToString();
Line 31: ASPxLabel3.Text = ViewState["MyViewState"].ToString();
Line 32: }

Posted 19-Feb-12 19:26pm

rockpune

Add a Solution

Comments

Varun Sareen 20-Feb-12 1:33am

Please tell the process how you are going? and when on which event you face this error?

rockpune 20-Feb-12 1:35am

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using DevExpress;

public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void ASPxButton1_Click(object sender, EventArgs e)
{
Response.Cookies.Add(new HttpCookie("MyCookie", ASPxTextBox2.Text));
}
protected void ASPxButton2_Click(object sender, EventArgs e)
{
Session["Mysession"] = ASPxTextBox3.Text;
}
protected void ASPxButton3_Click(object sender, EventArgs e)
{
ViewState.Add("MyViewState",ASPxTextBox4.Text);
}
protected void ASPxButton4_Click(object sender, EventArgs e)
{
ASPxLabel1.Text = Server.HtmlEncode(Request.Cookies["Mycookie"].Value);
ASPxLabel2.Text = Session["Mysession"].ToString();
ASPxLabel3.Text = ViewState["MyViewState"].ToString();
}
}

Varun Sareen 20-Feb-12 1:43am

Case sensitivity in Cookie name may be the issue also

Emad Al Hawary 20-Feb-12 1:44am

What about the exceptions?

5 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Mohammad A Rahman · Accepted Answer · 2012-02-19T19:36:00

Solution 2

Your are setting cookie value as MyCookie but retrieving as Mycookie. The name difference.

Setting Code:

C#

Response.Cookies.Add(new HttpCookie("MyCookie", ASPxTextBox2.Text));

Retirve Code:

C#

ASPxLabel1.Text = Server.HtmlEncode(Request.Cookies["Mycookie"].Value);

Hope it helps :)

Posted 19-Feb-12 19:36pm

Mohammad A Rahman

Comments

rockpune 20-Feb-12 1:42am

salamwalekum rahman bhai thanx...............

azhar

Mohammad A Rahman 20-Feb-12 1:48am

Does it solve your problem ?

rockpune 20-Feb-12 1:52am

ok

rockpune 20-Feb-12 1:52am

i get it

Varun Sareen 20-Feb-12 1:55am

accept this as your solution and rate it :)

Mohammad A Rahman 20-Feb-12 1:56am

Thanks Varun :)

Varun Sareen 20-Feb-12 2:06am

your welcome rahman

Mohammad A Rahman 20-Feb-12 1:56am

Does renaming the MyCookie name solve your problem?

Varun Sareen · Accepted Answer · 2012-02-19T19:35:00

Dear Friend,

As you haven't told in your problem that when you faced this error, I am giving you the solution for it on the basis of my presumption that you have clicked on the aspx button (ASPxButton4) first and as all the variable i.e., Session, View and Cookie are not yet initialized you are facing the problem :-

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
comes. In order to solve it you first have to initialize all the variables and then in the last click on the aspx button. Or you can initialize all the variables in the Page_Load event also.

Please refer this link for more details:- http://support.microsoft.com/kb/810098[^]

Thanks

Sudip Saha · Accepted Answer · 2012-02-19T19:43:00

Solution 3

C#

Session"Mysession"].ToString();
ViewState["MyViewState"].ToString();
USE
Convert.ToString( Session"Mysession"]);
Convert.ToString(ViewState["MyViewState"]);

Posted 19-Feb-12 19:43pm

Sudip Saha

Comments

Member 8821727_GhostAnswer 4-Jan-13 6:40am

'Session"Mysession"]' should be 'Session["Mysession"]' in your solution.

Emad Al Hawary · Accepted Answer · 2012-02-19T19:46:00

Solution 4

try to remove
using System.Linq;
Sometimes it is working without using LINQ

Maybe you're trying to access a member of a null reference; i.e. one of the variables here is null. Without knowing the line number it's difficult to say which

Posted 19-Feb-12 19:46pm

Emad Al Hawary

Updated 19-Feb-12 19:49pm

v2

**AmitGajjar** · Accepted Answer · 2012-02-19T19:52:00

Hi,

Most of the time Object Reference exception is cause by invalid name or accessing field for null object.

So, when you do coding. make sure you have all the required checking conditions. don't bother about number of lines. sometime people think, reducing line of code is good. Correct. but also minimize possibility of errors.

example :

if you are accessing cookies value Request.Cookies["Mycookie"].Value please use condition before this call.

C#

if(Request.Cookies["Mycookie"] != null)
{
ASPxLabel1.Text = Server.HtmlEncode(Request.Cookies["Mycookie"].Value);
}

OR

C#

ASPxLabel1.Text = 
        Request.Cookies["Mycookie"] ? "" : Server.HtmlEncode(Request.Cookies["Mycookie"].Value);

Hope this will help you in your code,

thanks
-Amit

Object reference not set to an instance of an object.

5 solutions

Solution 2

Solution 1

Solution 3

Solution 4

Solution 5

Add your solution here

Preview 0