How to return named tuples in C#?

Question

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;
    ...
}