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Question by RafaelCN · Jul 31, 2014 at 05:38 AM · c#nullreferenceexception

NullReferenceException

Let's say that I have a public static List in one script.

 public static List<String> ClientNames;

Calling it from other script in specifically OnGUI() function gives me NullReferenceException.

 ScriptName.ClientNames.Add("Rafael");   

It returns to me: NullReferenceException: Object reference not set to an instance of an object

I really have to do: ScriptName instanceName = GetComponent();?

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avatar image Arcadewiz · Jul 31, 2014 at 05:44 AM 0
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Are you calling a javascript from a c# script or vice-versa... ? If you are there are access issues between scripts..

avatar image RafaelCN · Jul 31, 2014 at 05:50 AM 0
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I'm already aware of that, I just use C#, thanks for the note. =)

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Answer by rutter · Jul 31, 2014 at 05:45 AM

As it turns out, any "reference" value can end up pointing at nothing, which your system calls "null". If you try to access a reference which is currently null, your computer will warn you that you're trying to access something which doesn't exist. You need to make sure it exists before accessing it.

It's important to distinguish two actions:

  • Declaring a variable gives it a name

  • Assigning a variable gives it a value

You've declared, but you haven't assigned.

 ClientNames = new List<String>();

You can do this all at once, too:

 public static List<String> ClientNames = new List<String>();


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avatar image RafaelCN · Jul 31, 2014 at 05:53 AM 0
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You are right, and I'm ashamed because I forgot a simple thing like that. Actually I did a test code before and I assigned the variable before, but then I erased everything and now it turns out that maybe I need glasses haha, just kidding. Thank you rutter!

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