Question

I got this class which raises same type of exception, how do i capture this exception and display appropriate error message. Here is what i do now.

public bool ChangePassword(oldPassword,newPassword)
{

  if(oldPassword != savedInDatabase)
{
  throw new ArgumentException("Your old password is not same as one saved in our database")
}

  if(string.IsNullOrEmpty(oldPassword) || string.IsNullOrEmpty(newPassword))
{
 throw new ArgumentException("Your old or new password is empty of null");
}

}

and i do the below,

try
{
}
catch(ArgumentException ex)
{
 if(ex.Message.contains("Your old or"))
{
  messagebox.show("Either your old or new password is empty or null")
}
...
}

Answer 1

Your example does not really justify custom exceptions. I say just display the original message.

However, if you really want to go down the path of custom exceptions, then another option is to create a single custom exception that takes an enum with all the different options, like such:

public class PasswordException : Exception
{
    public PasswordException(PasswordResult result) : base() { }
    public PasswordException(PasswordResult result, string message) : base(message) { }
    public PasswordException(PasswordResult result, string message, Exception innerException) : base(message, innerException) { }
}

public enum PasswordResult
{
    Success = 0,
    PasswordMismatch,
    PasswordEmpty,
    // and so forth
}