C#•16mo ago

✅ putting an object from an array into a variable changes the array

I'm trying to make a game using Raylib and I have a readonly array with a some levels in it I also have a variable called currentLevel which has levels[0] in it if I do

currentLevel.blocks.RemoveAt(0);

currentLevel.blocks.RemoveAt(0);

it doesn't only remove the first block from currentLevel it also removes it from levels[0]

26 Replies

Aaron•16mo ago

that's just a feature of reference types (classes), a variable just holds a reference to the actual data, not the data itself, so a copied variable still uses the original data if you want it to not do that, when setting currentLevel, you have to make copies of all the original data yourself

aOP•16mo ago

How do I make an exact copy of a class without having to enter all the info manually

Angius•16mo ago

Using some deep clone library would probably be the easiest

aOP•16mo ago

so you can't just make a direct copy with pure .net?

Angius•16mo ago

Not for reference types, no Well, I guess you could do the classic

var newThing = JsonSerializer.Deserialize<Thing>(JsonSerializer.Serialize(oldThing));

var newThing = JsonSerializer.Deserialize<Thing>(JsonSerializer.Serialize(oldThing));

aOP•16mo ago

how should I reset a level when the player dies then?

Angius•16mo ago

Could maybe try using records They're immutable, so you will always have to create a copy when changing it's values And making a copy should be as simple as with {}

Aaron•16mo ago

shadow copies though

MODiX•16mo ago

Angius

REPL Result: Success

record Foo(int Num);
var a = new Foo(69);
var b = a with {};
var c = b with { Num = 420 };

new {a, b, c}

record Foo(int Num);
var a = new Foo(69);
var b = a with {};
var c = b with { Num = 420 };

new {a, b, c}

Result: <>f__AnonymousType0#1<Foo, Foo, Foo>

{
  "a": {
    "num": 69
  },
  "b": {
    "num": 69
  },
  "c": {
    "num": 420
  }
}

{
  "a": {
    "num": 69
  },
  "b": {
    "num": 69
  },
  "c": {
    "num": 420
  }
}

Compile: 565.842ms | Execution: 107.002ms | React with ❌ to remove this embed.

Aaron•16mo ago

in the example they were using RemoveAt on a list

Angius•16mo ago

Huh, true

Aaron•16mo ago

would need to swap the list out for like, ImmutableList, then it can work

aOP•16mo ago

so like this?

c public static readonly ImmutableArray<World> levels = new ImmutableArray<World>{world, world2};

c public static readonly ImmutableArray<World> levels = new ImmutableArray<World>{world, world2};

Angius•16mo ago

More like the list of blocks would have to me immutable And then you could do

thing.TheList = thing.TheList.Skip(1).ToList();

thing.TheList = thing.TheList.Skip(1).ToList();

Although... I think that already clones the list

aOP•16mo ago

oh wait I have an idea I'm confused

Angius•16mo ago

Just throwing some possibilities for cloning All in all, I'd say your best bet would be to just find some deep clone library, preferably one based on source generators, and just clone your current level or whatever it is

aOP•16mo ago

but when I do this I get 5 not 2, so why isn't this a reference

Angius•16mo ago

Because integer isn't a reference type It's a value type

aOP•16mo ago

so what is the reference type when I do

world = levels[0];

world = levels[0];

Angius•16mo ago

Whatever is based on a class is a reference type Whatever is based on a struct is a value type

aOP•16mo ago

ahhh ok so is there really no easy way to load levels then?

Angius•16mo ago

Deep clone the level from the list into currentLevel

Angius•16mo ago

https://github.com/mostmand/Cloneable

GitHub

GitHub - mostmand/Cloneable: Auto generate Clone method using C# So...

Auto generate Clone method using C# Source Generator - GitHub - mostmand/Cloneable: Auto generate Clone method using C# Source Generator

Angius•16mo ago

Here, this looks promising

aOP•16mo ago

thanks a lot for your help

Accord•16mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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✅ putting an object from an array into a variable changes the array