Question

I want to make my class immutable. Obvious way would be to declare all fields as get; private set; and to initialize all fields in constructor. So clients must provide everything in constructor. The problem is that when there are ~10 or more fields passing them in constructor become very unreadable, because there are no labels for each field.

For example this is pretty readable:

info = new StockInfo
        {
            Name = data[0] as string,
            Status = s,
            LotSize = (int)data[1],
            ISIN = data[2] as string,
            MinStep = (decimal)data[3]
        };

compare to this:

new StockInfo(data[0] as string, s, (int) data[1], data[2] as string, (decimal) data[3])

And now imaging that I have 10 or more parameters.

So how can I make class immutable saving readability?

I can suggest only use the same formatting when using constructor:

info = new StockInfo(
            data[0] as string,           // Name
            s,                           // Status
            (int)data[1],                // LotSize
            data[2] as string,           // ISIN
            (decimal)data[3]             // MinStep
       );

Can you suggest something better?

Answer 1

No, it is not possible. Either you have immutable object or you want to have ability to modify object.

1. You can use named parameters.
2. You may consider passing other objects (and group parameters), so that one object will contain only parameters that are somehow very similar.

Looking at your code I may also suggest that you extract parameters first, so instead of passing something like data[0] as string you use string stockName = data[0] as string; and then use stockName. That should make your code more readable.

If you’re passing so many parameters to the constructor of your object it may be a good idea to revise your design. You may be violating Single Responsibility principle.