Question

Why is this working:

public int DoesEmailAddressExistsExcludingEmailAddressID(
    string emailAddress, 
    string invitationCode, 
    int emailAddressID = 0, 
    int For = (int) Enums.FOR.AC)

whereas this doesn’t

public int DoesEmailAddressExistsExcludingEmailAddressID(
    string emailAddress, 
    string invitationCode, 
    int emailAddressID = 0, 
    int For = Enums.FOR.AC.GetHashCode())

where AC is enum. Can enums’s hashcode change at runtime?

Answer 1

GetHashCode is a method. The return value of a method is not a compile time constant as code needs to be executed to determine the return value.
It doesn’t matter whether or not the method returns always the same.