CODEWITHSUNDEEP
c#datetimegetsettuples
Karim Ali
Karim Ali

Reputation: 563

How to return named tuples in C#?

I have a property that returns two items of type DateTime. When returning these values I have to reference them as Item1 and Item2. How do I return with custom names e.g. 

filter?.DateRanges.From
filter?.DateRanges.To

 

public Tuple<DateTime, DateTime> DateRanges
{
    get
    {
        From = DateTime.Now.AddDays(-1).Date.AddMonths(-1);
        To = DateTime.Now.AddDays(-1).Date;

        if (Preset != 0)
        {
            if (Preset == DatePreset.SpecificRange)
            {
                From = From.Date;
                To = To.Date;
            }
            else
            {
                var dateRange = DateTime.Today.AddDays(-1).GetDateRangeByPreset(Preset);
                From = dateRange.From;
                To = dateRange.To;
            }
        }

        return new Tuple<DateTime, DateTime>(From, To);
    }

usage:

var from = filter?.DateRanges.Item1;
var to = filter?.DateRanges.Item2;

Upvotes: 55

Views: 56077

Answers (2)

Matthew Watson
Matthew Watson

Reputation: 109792

Like this:

public (DateTime Start, DateTime End) DateRanges
{
    get
    {
        return (DateTime.MinValue, DateTime.MaxValue);
    }
}

Note: This requires a recent version of C# and .Net.

Incidentally, watch out for this usage pattern:

var from = filter?.DateRanges.Start;
var to = filter?.DateRanges.End;

That's inefficient because it causes two identical tuples to be created.

This is better:

var range = filter?.DateRanges;

if (range.HasValue)
{
    var from  = range.Value.Start;
    var to    = range.Value.End;
}

However note that tuples cannot be null (they are value types) so you could write it like so:

if (filter != null)
{
    var range = filter.DateRanges;
    var from  = range.Start;
    var to    = range.End;
    ...
}

ADDENDUM (2022):

Nowadays you can much more simply assign the values of a tuple to local variables. Now we can rewrite the last example above like so:

if (filter != null)
{
    var (from, to) = filter.DateRanges;
    ...
}

Upvotes: 90

Kolkil Kolk
Kolkil Kolk

Reputation: 156

class Program
{
    static void Main(string[] args)
    {
        test t = new test();
        Console.WriteLine(t.NamedTuple.start);
        Console.WriteLine(t.NamedTuple.stop);
        Console.Read();
    }
}

class test
{
    DateTime From;
    DateTime To;

    public (DateTime start, DateTime stop) NamedTuple
    {
        get
        {
            From = DateTime.Now.AddDays(-1).Date.AddMonths(-1);
            To = DateTime.Now.AddDays(-1).Date;
            return (From, To);
        }

    }
}

Upvotes: 3

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