Object refrence not set to an instance of an object in array

Question

i am very new to C# programming so my question may sound very silly

actualy i am creating an multidimensional string array like

public class master
    {
       public List<string> user_selected = new List<string>();
       public List<string> available = new List<string>();
       public List<string> bookedseats = new List<string>();

       public  string [] [] trackbooked=new string[30][] ;

    }

now i am assigning some values to it like

a[l].trackbooked[i][j] = pb.Name;

a is a list of object List<master> a = new List<master>(); a.Add(obj0); a.Add(obj1); a.Add(obj2); a.Add(obj3); a.Add(obj4);

can some one plz help.thank u in adv.

@quantdev it is inside a foreach loop so pb refers to the picture box — too_cool, Jun 06 '14 at 02:06
What is 'a'? An array of class master? Is it initialized properly? — Rick S, Jun 06 '14 at 02:07
You have a jagged array (an "array of arrays") not a multi-dimensional array. You are never instantiating the inner arrays in your snippet. — Preston Guillot, Jun 06 '14 at 02:07
@RickS a[l] is the object of the class i am changing the value of l — too_cool, Jun 06 '14 at 02:08
This really isn't a duplicate of that question, the crux of this question is a misunderstanding of jagged array syntax and initialization. — Preston Guillot, Jun 06 '14 at 02:14
@PrestonGuillot, did you bother to read the [first answer](http://stackoverflow.com/a/4660186/2589202)? Jagged arrays are right in there. _Any_ time you see a null reference error, mark it as a dupe of that, no question. — crthompson, Jun 06 '14 at 02:35

score 1 · Accepted Answer · answered Jun 06 '14 at 02:08

1

You've only initialized one dimension of your multidimensional array. See msdn for all the ways you can initialize a multidimensional array.

 public  string [,] trackbooked=new string[30,30] ;

answered Jun 06 '14 at 02:08

Jason Nesbitt

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score -4 · Answer 2 · answered Jun 06 '14 at 02:08

-4

pb.Name.Tostring(); I would venture to guess that whatever pb is that its NAME value isn't returned as a string. You should be able to use the above command to correct your issue.

answered Jun 06 '14 at 02:08

Ermac Pd

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...that wouldn't cause a `NullReferenceException`.. – Simon Whitehead Jun 06 '14 at 02:17

Object refrence not set to an instance of an object in array

2 Answers2