How to return 2 value in c# method

Question

I created the function of c# to compare the price in my project.

public static decimal? SpecialPrice(decimal w, decimal p)
{
    if (w < p)
    {
        return p;
    }
    else if (w > p && p > 0)
    {
        //return (w , p);
    }
    else
    {
        return w;
    }
}

I want to return two variable ( w and p) when w > p and p >0 , but I don't know how can I return like that. Anyone know about it?

Answer 1

Your choices for returning multiple values to calling code are:

1. Out params
2. Ref params
3. Return a struct/object that contains multiple values, or another type like a collection

Basically, #1 and #2 let you have method arguments that let you pass values back to the calling code. See here for examples & reference:

http://msdn.microsoft.com/en-us/library/ee332485.aspx (out params)

http://msdn.microsoft.com/en-us/library/14akc2c7.aspx (ref params)

For #3, you would use a return value different from decimal?. For example, you could declare a class with two properties and return an instance of that. Or return a List<decimal> or some other type that can hold multiple values.

It's not really clear to me what the intent of your code is, so you'll need to decide which approach is best for you.

Answer 2

In C# you can not return two values from methods. It's better two return an array or some collection type which allows to hold more values than one.

Maybe something like this:

public static decimal[] SpecialPrice(decimal w, decimal p)
{
   if (w < p)
   {
      return new decimal[] { p };
   }
   else if(w > p && p > 0)
   {
       return new decimal[] { w, p };
   }
   else
   {
       return new decimal[] { w };
   }
}

If it's important to know which value is which after this method executes, you could use more sophisticated collection classes like the Dictionary class which lets you refer to each of its values by name.

I wouldn't create a new struct or class in this situation as I think the array size is a really easy indication of how many values are being returned where classes and structs will have the same number of variables before calling this method and after, making it harder to tell how many values were returned.

Answer 3

You could use a Tuple:

public static Tuple<decimal?, decimal?> SpecialPrice(decimal w, decimal p)
{
   if (w < p)
   {
      return new Tuple<decimal?, decimal?>(p, null);
   }
   else if(w > p && p>0)
   {
      return new Tuple<decimal?, decimal?>(p, w);
   }
   else
   {
      return new Tuple<decimal?, decimal?>(w, null);
   }
}

Answer 4

You can't have it return more than one object. However, you can just make the object that you return more complex.

public struct PandW
{
   public decimal? p{get;set;}
   public decimal? w{get;set;}
}

Then change your method to return PandW object:

 public static PandW SpecialPrice(decimal w, decimal p)
 {
 PandW temp;
if (w < p)
{
  temp.w=null;
  temp.p=p;
  return temp;
}else if(w > p && p>0){
   temp.w=w;
  temp.p=p;
  return temp;
}else{
   temp.w=w;
   temp.p=null;
   return temp;
}

}

Answer 5

There are several ways to return multiple values:

• You can create a class or a struct with multiple fields, and return an instance from your method
• You can add output parameters to your method
• You can return an array
• You can return a KeyValuePair (not recommended)

In this particular case, I would prefer the first way to return two values:

class PriceRet {
    decimal? w;
    decimal? p;
}
PriceRet SpecialPrice(decimal w, decimal p) {
    var res = new PriceRet();
    if (w < p) {
        res.p = p;
    } else if(w > p && p>0) {
        res.w = w;
        res.p = p;
    } else {
        res.w = w;
    }
    return res;
}

Answer 6

Try KeyValuePair<decimal,decimal>(w,p) but you need to change your return type to KeyValuePair.

Hope that helps.

Answer 7

That's why structures where invented

public struct PricePoints
{
    decimal? w, p;

    public PricePoints SpecialPrice()
    {
        PricePoints res;
        if (w < p)
        {
            res.p = p;
            res.w = null;
        }
        else if (w > p && p > 0)
        {
            res = this;
        }
        else
        {
            res.w = w;
            res.p = null;
        }
        return res;
    }
}

Answer 8

the best way is to return object that has two properties, and also you can use the out variable

public static testhelper SpecialPrice(decimal w,decimal p)
{

//set your values in the object 
var Obj=new testhelper{
w=some value,
p= some value 
};
//// your code 

  if (w < p)
 {
   return p;
 }else if(w > p && p>0){
   //return (w , p);
 }else{
   return w;

} return Obj; }

public class testhelper{
  public int p{get;set;}
  public int w{get;set;}
 }