Is it possible for a function to return two values?

Question

Is it possible for a function to return two values? Array is possible if the two values are both the same type, but how do you return two different type values?

Answer 1

To return 2 values I usually use Pair class from http://blog.o-x-t.com/2007/07/16/generic-pair-net-class/. If you need to return from method 2 values that describe the range, e.g. From/To or Min/Max, you can use FromToRange class.

public class FromToRange<T>
    {
        public T From { get; set; }
        public T To { get; set; }

        public FromToRange()
        {
        }

        public FromToRange(T  from, T  to)
        {
            this.From = from;
            this.To = to;
        }
        public override string ToString()
        {
            string sRet = String.Format("From {0} to {1}", From, To);
            return sRet;
        }
        public override bool Equals(object obj)
        {
            if (this == obj) return true;
            FromToRange<T> pair = obj as FromToRange<T>;
            if (pair == null) return false;
            return Equals(From, pair.From) && Equals(To, pair.To);
        }

        public override int GetHashCode()
        {
            return (From != null ? From.GetHashCode() : 0) + 29 * (To != null ? To.GetHashCode() : 0);
        }

    }

Answer 2

In a word, no.

But you can define a struct (or class, for that matter) for this:

struct TwoParameters {
    public double Parameter1 { get; private set; }
    public double Parameter2 { get; private set; }

    public TwoParameters(double param1, double param2) {
        Parameter1 = param1;
        Parameter2 = param2;
    }
}

This of course is way too specific to a single problem. A more flexible approach would be to define a generic struct like Tuple<T1, T2> (as JaredPar suggested):

struct Tuple<T1, T2> {
    public T1 Property1 { get; private set; }
    public T2 Property2 { get; private set; }

    public Tuple(T1 prop1, T2 prop2) {
        Property1 = prop1;
        Property2 = prop2;
    }
}

(Note that something very much like the above is actually a part of .NET in 4.0 and higher, apparently.)

Then you might have some method that looks like this:

public Tuple<double, int> GetPriceAndVolume() {
    double price;
    int volume;

    // calculate price and volume

    return new Tuple<double, int>(price, volume);
}

And code like this:

var priceAndVolume = GetPriceAndVolume();
double price = priceAndVolume.Property1;
int volume = priceAndVolume.Property2;

Answer 3

It is not directly possible. You need to return a single parameter that wraps the two parameters, or use out parameters:

object Method(out object secondResult)
{
    //...

Or:

KeyValuePair<object,object> Method()
{
   // ..

Answer 4

You could use the out parameter.

int maxAge;
int minAge;
public int GetMaxAgeAndMinAge(out int maxAge, out int minAge)
{
    MaxAge = 60;
    MinAge = 0;
    return 1; //irrelevant for this example since we care about the values we pass in
}

I really tend to stay away from this, I think that it is a code-smell. It works for quick and dirty though. A more testable and better approach would be to pass an object that represents your domain (the need to see two these two values).

Answer 5

you can try this

public IEnumerable<string> Get()
 {
     return new string[] { "value1", "value2" };
 }

Answer 6

It is not possible to return more than one value from a function, unless you are returning a type that contains multiple values in it (Struct, Dictionary, etc). The only other way would be to use the "out" or "ref" keywords on the incoming parameters.