Instantiate an object in an array

Question

4.40/5 (2 votes)

See more:

Hi,

I'm trying to Instantiate a new object and store the object into an array. I am receiving "Object reference not set to an instance of an object." I can't figure out what I've done wrong, it looks right to me. Any help is greatly appreciated.

MyExcel[] myexcel = null;
int excel = 0;
...
foreach (KeyValuePair<string, string> kvp in Common.divisionDictionary)
{
    myexcel[excel] = new MyExcel();         // Instantiate an instance of Excel

    path = Common.SpreadsheetDirectory;
    ...
}

I'm receiving the error on:

myexcel[excel] = new MyExcel();

However if I assign it like this it works perfect:

MyExcel Excel = new MyExcel();

Thank you,
Glenn

Posted 10-Dec-10 9:27am

gmhanna

Add a Solution

Comments

Dr.Walt Fair, PE 10-Dec-10 19:02pm

The error is exactly what it says it is. You need to initialize the array before you assign anything to its members, since the members don't exist yet.

2 solutions

Solution 2

You didn't allocate memory for the array.

For instance, changing from

MyExcel[] myexcel = null;

to (say)

MyExcel[] myexcel = new MyExcel[10];

would fix your program.
:)

Posted 10-Dec-10 9:40am

CPallini

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)

Richard MacCutchan · Accepted Answer · 2010-12-10T09:33:00

Solution 1

MyExcel[] myexcel = null;

...

myexcel[excel] = new MyExcel();         // Instantiate an instance of Excel

You cannot store an item into an array that does not exist. You need to allocate some entries to myexcel - at least as many as will be encountered in your foreach loop.

Posted 10-Dec-10 9:33am

Richard MacCutchan