Does copying objects reduce the performance?

Question

First of all, I don't know if this is called "copying" an object, so the question title may be wrong. What I have is a custom class called File which has inside a bunch of lists (1000+ numbers in 5-6 lists) and some other properties. I have all my files in a List to be able to access them (LoadedFiles). My question is: if I'm writing a method and I don't want to write: ``` DoSomeOperation(LoadedFiles[2]); ``` but instead: ``` File file2 = new File(); file2 = LoadedFiles[2]; DoSomeOperation(file2); ``` Is this a bad practice? Or the compiler is clever enough to know that it's the same object and access it directly from the original list (LoadedFiles).

Accepted Answer

Actually your class is a reference type which means that the line file2 = LoadedFiles[2] will only copy a reference pointer to the object that was created, you're not copying the contents of the object into a new object.

So as far as performance is concerned you a creating a new instance of a file:

```
 File file2 = new File();
```

Then you're immediately switching the reference to a different object

```
file2 = LoadedFiles[2];
```

Thus releasing the reference to the object you had just created. This will cause needless garbage collection to occur. It's better to just do File file2 = LoadedFiles[2] if it makes a difference to you stylistically.

Best place to look into reference types vs value types is the C# Language specification http://www.microsoft.com/en-us/download/details.aspx?id=7029 on page 77.

Does copying objects reduce the performance?

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