C# Static method modifying an object

Question

Imagine something like this...

public class Result
{
    public string Name {get; set;}

    public int Score {get; set;}

    public bool Pass {get; set;}
}

And a static method...

public static Result SetPass(this Result result)
{
    result.Pass = result.Score > 50;

    return result;
}

My question is do I have to return the result or is it already modified in place? Could I make the return type void and then iterate through a collection of results and amend in place like this...

foreach (var result in results)
{
    result.SetPass();
}

or do I need to return the result object and re-assign?

Marc Gravell · Accepted Answer · 2020-01-15 16:00:20Z

7

Since Result is a class, it is currently modified on the single object - essentially in-place; this is passing a reference by-value. As such, there is no point having a return value here.

If Result was a struct, you would need to either return a new value, or use (ref this Result result) (making it pass a value by-reference); note that the compiler is lenient in this case, and allows the ref to be used implicity in this scenario (ref usually needs to be explicit at both caller and callee).

edited Jan 15, 2020 at 16:00

answered Jan 15, 2020 at 15:57

Marc Gravell

1.1m273 gold badges2.6k silver badges3k bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

C# Static method modifying an object

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related