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C#

Posted by richardking4
richardking4
2,997 Points

System.NullReferenceException, filename unknown (Tower Defense project)

Hello all — I'm getting the following error when running my code:

Unhandled exception reads: System.NullReferenceException: Object reference not set to an instance of an object at TreehouseDefence.Game.Main () <0x4087fd50 + 0x0041b> in <filename unknown>:0

It compiles just fine. Here's a snapshot:

https://w.trhou.se/kfaazdqhe8

I guess I have two questions:

1) Why am I not getting details on where this exception is stemming from? Even if I run the compiler using -debug I don't get any extra details. All I can work out is that it's coming from somewhere within the try ... catch block in my Main() method.

2) What part did I mess up?? Hah.

1 Answer

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

I was able to replicate your message by running "Game.exe", but I noticed that it had been built before the last edit to "Game.cs".

So I rebuilt the project and when I run that, I get no error. So it seems you'd already fixed the issue in the source but just had not rebuilt yet.

richardking4
richardking4
2,997 Points

You won't believe it...

I've been running this to compile for a while:

clear && mcs -out:Game.exe *.cs && mono Game.exe

But then I got lazy and started running it as:

clear && mcs *.cs && mono Game.exe

...little realising that we'd subsequently added Exceptions.cs in the videos and it was now compiling as Exceptions.exe... :)

Oops. Thanks for taking the time to look, now I'll know to check that!

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

I just figured that other executable was from some extra-curricular experimentation. :wink:

Happy coding!