Checking if a variable has a value

I thought I've done this before with no issue.
Compile error Use of unassigned local variable `SelectedShip
Trying to check if Selectedship has a value
ive also tried
if(SelectedShip){}

Code (csharp):

1.  
2. if(SelectedShip != null) {
3.  
4. SelectedShip.SetActive(true);
5.  
6. }
7.  

Code (csharp):

1.  
2. publicvoid OnClicked(Button button) {
3.  
4. GameObject SelectedShip;
5.  
6. foreach(GameObject child in ShipWrapperTransform) {
7.  
8.   if (child.name == button.name){
9.  
10.      SelectedShip = child;
11.  
12.    }else{
13.  
14.    }
15.  
16. }
17.  
18. if(SelectedShip != null) {
19.  
20.    SelectedShip.SetActive(true);
21.  
22. }
23.  
24. }
25.  
26.  

 

I just realized I can just assign null to it to fix it.
GameObject SelectedShip = null;

Still seems like there should be a way to check though.

 

it's a c# thing... the code above that check has the option for selectedship to never be assigned anything (i.e. the else clause).


edit: it'll work the way you are expecting it to if the declaration is outside the function

i.e.

Code (csharp):

1.  
2. public class someclass : ...
3. {
4.     GameObject myobj;
5.  
6.     public void TestFunction()
7.     {
8.         if(myobj)
9.         {
10.  
11.         }
12.    }
13. }
14.  

 

like the error says it's a local unassigned. As soon as you take out the GameObject SelectedShip to the class instead of the method. it will work without setting it explizit to null.

I think it's because if you have a variable in the class not assigned with a value, it's automatically set to it's default values.
GameObject, Lists, Arrays -> null
int float -> 0
Vector -> Vecter.Zero
bool -> false

as soon you have this declaration in an method it's not recognized and therefore the error.

Code (CSharp):

1. GameObject SelectedShip;
2.  
3. publicvoid OnClicked(Button button) {
4.    foreach(GameObject child in ShipWrapperTransform) {
5.       if (child.name == button.name){
6.          SelectedShip = child;
7.       }else{
8.       }
9.    }
10.  
11.    if(SelectedShip != null) {
12.       SelectedShip.SetActive(true);
13.    }
14. }

 

will nothing change to the error if you set SelectedShip in the else, tried it out

 

Ahh ya lol.
Ya I come from a strong PHP background. I never used classes with PHP.

Thanks guys I appreciate it. I was like what the heck for half an hour on that lol.
Actually I think I knew this but forgot. I was away from Unity for 3 months then just came back again to work on my project and kind of forgot some stuff.

It fades pretty fast apparently lol.

 

hmm good point, there might be no execution of the foreach i.e. no children of the transform...

 

Check out this page. Don't just do obj != null, also do !obj.Equals(null).

https://answers.unity.com/questions/1420784/if-something-null-not-good-enough.html

 

necro?