Problems passing object array

[tcomer]

This is what I'm trying to do:

class MyClass
{
private MyObject [] object;

public MyClass()
{
object = new MyObject[10];
MyFunction(ref object);
....

protected MyFunction(ref MyObject [] object)
{
object[0].myVar= "value";
....

this is giving me a NullReferenceEx ception on the statement in
MyFunction. The constructor of the object initializes all variables to
a default value.

[Jon Skeet [C# MVP]]

Re: Problems passing object array

tcomer <tcomer@gmail.c omwrote:

This is what I'm trying to do:
>
class MyClass
{
private MyObject [] object;
>
public MyClass()
{
object = new MyObject[10];
MyFunction(ref object);
...
>
protected MyFunction(ref MyObject [] object)
{
object[0].myVar= "value";
...
>
this is giving me a NullReferenceEx ception on the statement in
MyFunction. The constructor of the object initializes all variables to
a default value.

Creating an array of a class type doesn't create any instances of that
type - it creates an "empty" array with as many "slots" as you've asked
for, with the value in each "slot" being null to start with. It sounds
like you want to do:

for (int i=0; i < object.Length; i++)
{
object[i] = new MyObject();
}

before your method call.

(By the way, I assume you're not *really* using "object" as a variable
name... I really hope not!)

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Dave Sexton]

Re: Problems passing object array

Hi Jon,

(By the way, I assume you're not *really* using "object" as a variable
name... I really hope not!)

It wouldn't even compile unless it's escaped with the literal token "@"
anyway:

protected MyFunction(ref MyObject[] @object) { ... }

But I agree, that's ridiculous :)

--
Dave Sexton

"Jon Skeet [C# MVP]" <skeet@pobox.co mwrote in message
news:MPG.1fb706 64fa038b9298d5c f@msnews.micros oft.com...

tcomer <tcomer@gmail.c omwrote:

>This is what I'm trying to do:
>>
>class MyClass
>{
> private MyObject [] object;
>>
>public MyClass()
>{
> object = new MyObject[10];
> MyFunction(ref object);
>...
>>
>protected MyFunction(ref MyObject [] object)
>{
> object[0].myVar= "value";
>...
>>
>this is giving me a NullReferenceEx ception on the statement in
>MyFunction. The constructor of the object initializes all variables to
>a default value.

>
Creating an array of a class type doesn't create any instances of that
type - it creates an "empty" array with as many "slots" as you've asked
for, with the value in each "slot" being null to start with. It sounds
like you want to do:
>
for (int i=0; i < object.Length; i++)
{
object[i] = new MyObject();
}
>
before your method call.
>
(By the way, I assume you're not *really* using "object" as a variable
name... I really hope not!)
>
--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[tcomer]

Re: Problems passing object array

No, that was just the name that I used in the example.. I know better
;)

That solved my problem, thanks a lot! I've moved from C++ to C# and I'm
still trying to get used to the differences between the two. Much
appreciated!