object reference not set to an instance of an object

Question

2.00/5 (1 vote)

See more:

I have the following code on my class:

C#

public void addproduct()
    {
        string Lname = AddEmployee._emp.txtEmpLname.Text.ToString();
        string Fname = AddEmployee._emp.txtEmpFname.Text.ToString();
        string EmpDepart = AddEmployee._emp.drpDepartment.SelectedValue.ToString();
        string EmpStatus = AddEmployee._emp.drpStatus.SelectedValue.ToString();
        string AddName = Lname + "," + "  " + Fname;

        SQcon.Open();
        SQcmd = new SqlCommand("INSERT INTO ProductRecord Values ('" +AddName + "' , '" + EmpDepart + "' , '" + EmpStatus + "')",SQcon);
        SQcmd.ExecuteNonQuery();

        SQread.Close();
        SQcon.Close();
    }

and on my code behind:

C#

protected void btnSubmit_Click(object sender, EventArgs e)
        {
            DatabaseModule.addproduct();
        }

and I'm getting this error
object reference not set to an instance of an object

how do I resolve this

Posted 31-Mar-14 17:22pm

JB0301

Add a Solution

Comments

Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ) 31-Mar-14 23:25pm

On which line?

JB0301 31-Mar-14 23:26pm

here:
string Lname = AddEmployee._emp.txtEmpLname.Text.ToString();
string Fname = AddEmployee._emp.txtEmpFname.Text.ToString();
string EmpDepart = AddEmployee._emp.drpDepartment.SelectedValue.ToString();
string EmpStatus = AddEmployee._emp.drpStatus.SelectedValue.ToString();

[no name] 1-Apr-14 0:47am

In which line you got that error

3 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)

Sergey Alexandrovich Kryukov · Answer 1 · 2014-03-31T18:00:00

First of all, the property Text should be already of a string type, but you are calling ToString() on it, to get the same very string. This is totally pointless.

And you still did not show where the exception with the message "Object reference not set to an instance of an object" is thrown. You could see it from the exception stack of from the debugger. What this exception tells you if it is thrown on the expression AddEmployee._emp.txtEmpLname.Text.ToString()? It means that AddEmployee can be null, otherwise AddEmployee._emp can be null, otherwise AddEmployee._emp.txtEmpLname can be null, and finally, AddEmployee._emp.txtEmpLname.Text can be null. You could have examined this expression under the debugger.

After all, you cannot ask for help every time something like that happens; you need to be able to do it by yourself.

Not to worry. This is one of the very easiest cases to detect and fix. It simply means that some member/variable of some reference type is dereferenced by using and of its instance (non-static) members, which requires this member/variable to be non-null, but in fact it appears to be null. Simply execute it under debugger, it will stop the execution where the exception is thrown. Put a break point on that line, restart the application and come to this point again. Evaluate all references involved in next line and see which one is null while it needs to be not null. After you figure this out, fix the code: either make sure the member/variable is properly initialized to a non-null reference, or check it for null and, in case of null, do something else.

Please see also: want to display next record on button click. but got an error in if condition of next record function "object reference not set to an instance of an object"[^].

Sometimes, you cannot do it under debugger, by one or another reason. One really nasty case is when the problem is only manifested if software is built when debug information is not available. In this case, you have to use the harder way. First, you need to make sure that you never block propagation of exceptions by handling them silently (this is a crime of developers against themselves, yet very usual). The you need to catch absolutely all exceptions on the very top stack frame of each thread. You can do it if you handle the exceptions of the type System.Exception. In the handler, you need to log all the exception information, especially the System.Exception.StackTrace:
http://msdn.microsoft.com/en-us/library/system.exception.aspx[^],
http://msdn.microsoft.com/en-us/library/system.exception.stacktrace.aspx[^].

The stack trace is just a string showing the full path of exception propagation from the throw statement to the handler. By reading it, you can always find ends. For logging, it's the best (in most cases) to use the class System.Diagnostics.EventLog:
http://msdn.microsoft.com/en-us/library/system.diagnostics.eventlog.aspx[^].

Good luck,

—SA

JB0301 · Answer 2 · 2014-03-31T21:48:00

Solution 3

I was able to fix this by putting the following codes on my codebehind

C#

public static Default _def = new Default();

C#

_def = this;

Thankyou for your answers

Posted 31-Mar-14 21:48pm

JB0301

gagandeep.pratihar · Answer 3 · 2014-03-31T18:51:00

Solution 2

I think DataBaseModule is not initialized thats why ur getting that exception

Posted 31-Mar-14 18:51pm

gagandeep.pratihar