CODEWITHSUNDEEP
c#
Lou Phelps
Lou Phelps

Reputation: 1

Dispose() affecting a variable it shouldn't?

I'm new to C# and I'm having trouble while disposing of a variable, because it seems to affect another variable that it shouldn't. A simplified version of the code is:

class Game
{
    Bitmap image;

    public Game(Bitmap image)
    {
        this.image = image;
    }
}

...
Bitmap tempConvert;
...
tempConvert = new Bitmap(100, 100);
games.Add(new Game(tempConvert));
tempConvert.Dispose();

It should be pretty simple: tempconvert gets passed on to Game.image then gets disposed of. Except that tempConvert.Dispose() seems to affect Game.image as well. There's no pointers or adresses or anything, so I don't know why Game.image is affected. Removing tempConvert.Dispose() solves the problem, but creates a massive memory leak.

So then, why is tempConvert.Dispose() affecting Game.image if tempConvert's contents had already been passed on?

Upvotes: 0

Views: 58

Answers (2)

Maarten
Maarten

Reputation: 22945

You are passing a reference of the Bitmap object to your Game class, not the contents of the bitmap. You create 1 Bitmap object, not more; the Bitmap object is used by your initial code and the Game object.

Therefore disposing it in your initial code will affect your Game object.

Upvotes: 2

user12864
user12864

Reputation: 591

Bitmap is a reference type. When you pass it to new Game, you're passing a reference to the same instance of Bitmap. Either make another copy of the Bitmap or have the Game class dispose of it, depending on the desired lifecycle and where else the Bitmap is being used.

Upvotes: 4

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