CODEWITHSUNDEEP
c#-4.0referencestruct
crazyPixel
crazyPixel

Reputation: 2330

Change struct values from a different class

I am trying to change a struct values (located in class A) from another class (class B per say) I wrote a method to get the struct (the method is located in class A) but all I get is a shallow copy (the values do not really change...) any help?

Upvotes: 1

Views: 145

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1500505

Yes, that's what happens with structs. You need to make the changes locally, then shallow copy back again. For example:

public class Foo
{
    public Point Location { get; set; }
}

public class Bar
{
    private Foo foo = new Foo();

    public void MoveFoo()
    {
        Point location = foo.Location;
        location.X += 10;
        location.Y += 20;
        // Copy it back
        foo.Location = location;
    }
}

Personally I try to avoid making structs mutable in the first place - but will often given them what I call "pseudo-mutator" methods which return a new value with appropriate changes. So for example, for a Point struct I might have a method like this:

public Point TranslatedBy(int dx, int dy)
{
    return new Point(x + dx, y + dy);
}

Then the MoveFoo method above would be:

foo.Location = foo.Location.TranslatedBy(10, 20);

Upvotes: 3

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