Best Practice Return Value vs Exception vs Enum [closed]

Answer 1

I usually use this approach in my projects:

signature:

bool TryLogin(string username, string password, out User user);

usage:

User user;
if(userService.TryLogin(username, password, out user)))
{
    // do stuff with user
}
else 
{
    // show "login failed"
}

You could expand this to return your Enum:

signature:

enum LoginResult
{
    Successful
    UnknownUser,
    WrongPassword
}

LoginResult TryLogin(string username, string password, out User user);

usage:

User user;
LoginResult loginResult;
if((loginResult = userService.TryLogin(username, password, out user)) == LoginResult.Successful)
{
    // do stuff with user
}
else 
{
    // do stuff with loginResult
}