How do you implement GetHashCode for structure with two string, when both strings are interchangeable

Question

I have a structure in C#:

public struct UserInfo
{
   public string str1
   {
     get;
     set;
   }

   public string str2
   {
     get;
     set;
   }           


        

Answer 1

1. As a general rule, a simple way to generate a hashcode for a class is to XOR all the data fields that can participate in generating the hash code (being careful to check for null as pointed out by others). This also meets the (artificial?) requirement that the hashcodes for UserInfo("AA", "BB") and UserInfo("BB", "AA") are the same.

2. If you can make assumptions about the use of your class, you can perhaps improve your hash function. For example, if it is common for str1 and str2 to be the same, XOR may not be a good choice. But if str1 and str2 represent, say, first and last name, XOR is probably a good choice.

Although this is clearly not meant to be a real-world example, it may be worth pointing out that: - This is probably a poor example of use of a struct: A struct should normally have value semantics, which doesn't seem to be the case here. - Using properties with setters to generate a hash code is also asking for trouble.