Format a Decimal to Currency

Question

I have a list of decimals that I want to be able to format as US currency. I know I can do this with string.format but if I convert the decimals to a string they no long sort properly

1234.98
91234.12
541234.12

When converted to currency using string.format they will sort in this order

$91,234.12
$541,234.12
$1,234.98

I want them to stay as decimals so they sort correctly as

$541,234.12
$91,234.12
$1,234.98

Answer 1

Keep them as decimals within the list or container you are using to sort, and simply use string format on them when displaying. I don't understand the need have them as both a string and a decimal at the same time when you can display it anyway you wish.

Answer 2

I see two main options for you here. The first is to zero-pad your numbers ( $001,234.98 ) which seems like it would directly oppose most user's preferred experiences.

Another option could be to create a type for currency:

public class Currency : IComparable
{
    public decimal Value { get; set; }

    public int CompareTo(Currency b)
    {
        return Value.CompareTo(b.Value);
    }

    public override string ToString()
    {
        return Value.ToString("C");
    }
}

You'd want to override Equals and GetHashCode , of course. This would display sorted as expected (control properties permitting), but it would also display as expected. You might want to make the class into an immutable struct , of course, too. But this is just meant to show the gist.

A class like this would also provide very good LINQ support, in that you could have an IEnumerable<T> and simply call OrderBy(c => c) . You could even print out the values on lines by calling string.Join(Environment.NewLine, coll.OrderBy(c => c)) , which is very clean.

Of course, a class like this should only be used for UI code. You wouldn't want to deal with serializing it or anything like that, since it'd provide unnecessary overhead.

Answer 3

Create a class that holds the decimal and its appropriate formatted string. Use Linq to sort the class objects by the decimal.