Having trouble with arguments and classes in VB - vb.net

Question

I am having trouble with getting classes to work and passing arguments for those classes. i have figured out most of the other Errors i had on my own, but there is one error that is really bugging me. the error i am getting is for "objAttendee". the error says "Argument not specified for parameter "strFirstName" of public Sub New(ByVal strFirstName As String, ByVal strLastName As String, ByVal strCourses As String, ByVal intDays As String)". i am not at all sure how to fix this problem.
can anyone help me out with this?
Option Strict On
Public Class Attendee
Dim objAttendee As New Attendee
'class variables
Private _strFirstName As String
Private _strLastName As String
Private _strCourses As String
Private _intDays As Integer
Private _decTotal As Decimal
Private _decCostPerDay As Decimal = 350D
Private _decPreConferenceCost As Decimal = 675D
Sub New(ByVal strFirstName As String, ByVal strLastName As String, ByVal strCourses As String, ByVal intDays As String)
'Contructor
_strFirstName = strFirstName
_strLastName = strLastName
_strCourses = strCourses
_intDays = Convert.ToInt32(intDays)
End Sub
Function ComputeCourseCosts() As Decimal
'Calculates the cost if a pre-conference course is not selected
_decTotal = _intDays * _decCostPerDay
Return _decTotal
End Function
Function ComputePreConferenceCosts() As Decimal
'Calculates the cost if a pre-conference course is selected
_decTotal = _intDays * _decCostPerDay + _decPreConferenceCost
Return _decTotal
End Function
End Class

Answer 1

"Argument not specified for parameter ".....
Plutonix told you the origin of the issue :
You're declaring a Attendee object within your Attendee Class (which doesn't really makes sense)
Public Class Attendee
Dim objAttendee As New Attendee ' <- offending code :P
But the constructor of that class is declared as follows :
Sub New(ByVal strFirstName As String, ByVal strLastName As String, ByVal strCourses As String, ByVal intDays As String)
And you don't have a constructor without any parameter like :
Public Sub New() ' No parameter required
' ...
End Sub
And you don't have to create/declare such variant of Attendee constructor, otherwise, you must have to define default values for _strFirstName, _strLastName, _strCourses and _intDays !
I think that... you were in the urge to test your Attendee class, and declared an Attendee variable inside it ;) .
No, you should declare Dim objAttendee As New Attendee(...) outside your class (in the main block of your program for example) with the appropriate parameters.
Private Sub ShowMyClass(sender As Object, e As EventArgs) Handles Button1.Click
Dim objAttendee As New Attendee("Simpson", "Homer", "Courses", "48")
MessageBox.Show(objAttendee.ComputeCourseCosts().ToString())
End Sub