Separate message for condition in vb document - vb.net

Question

I am creating a seat booking system in visual basic for coursework and it has to allow users to book seats from rows A to E. For row B, I have set it so that there are no seats remaining, however the message simply tells the user that there are not enough seats and that the maximum available seats is 0. I need the code to tell users that there are no seats remaining. My code is as follows:
Public Class Form1
Private Sub ListBox2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox2.SelectedIndexChanged
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim rowNumber As Integer
Dim SeatsData As String(,) = {{"booked", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", "A10"},
{"booked", "booked", "booked", "booked", "booked", "booked", "booked", "booked", "booked", "booked"},
{"C1", "C2", "C3", "C4", "C5", "C6", "C7", "C8", "C9", "C10"},
{"D1", "booked", "booked", "D4", "D5", "D6", "D7", "D8", "D9", "D10"},
{"E1", "E2", "booked", "booked", "booked", "E6", "E7", "E8", "E9", "E10"}}
If ListBox2.Text = "A" Then
rowNumber = 0
ElseIf ListBox2.Text = "B" Then
rowNumber = 1
ElseIf ListBox2.Text = "C" Then
rowNumber = 2
ElseIf ListBox2.Text = "D" Then
rowNumber = 3
ElseIf ListBox2.Text = "E" Then
rowNumber = 4
End If
FindSeats(rowNumber, ListBox1.Text, SeatsData)
End Sub
Function FindSeats(ByVal RowNumber As Integer, ByVal NumSeats As Integer, SeatsData As Array) As String
Dim i As Integer = 0
Dim arrayPos As Integer = 0
Dim maxSeats As Integer = 0
Dim FirstSeat As String = 0
Dim LastSeat As String = 0
Dim Seatsfound As Boolean = False
Dim returnMsg As String = ""
Do While Seatsfound = False
Dim seatChar As String = SeatsData(RowNumber, arrayPos)
arrayPos = arrayPos + 1
If seatChar = "booked" Then
i = 0
Else
If i = 0 Then
FirstSeat = seatChar
End If
i = i + 1
If i > maxSeats Then
maxSeats = i
End If
End If
If i = NumSeats Then
LastSeat = seatChar
If FirstSeat = LastSeat Then
returnMsg = "Found seat: " + FirstSeat
Else
returnMsg = "Found seats: " + FirstSeat + " - " + LastSeat
End If
MsgBox(returnMsg)
Label3.Text = returnMsg
Seatsfound = True
Exit Do
End If
If arrayPos = 10 Then
returnMsg = "Not enough available seats, maximum available seats: " + CStr(maxSeats)
MsgBox(returnMsg)
Label3.Text = returnMsg
Exit Do
End If
Loop
End Function
End Class
How can I set my code so that it tells the user "there are no remaining seats in this row" or something?

Answer 1

Without using a custom class to design your problem domain, a simple approach is using a Dictionary
For example
Sub Main
Dim seats = new Dictionary(Of string, List(Of String))()
seats.Add("A", new List(Of String) FROM {"A1", "A2", "A3"})
seats.Add("B", new List(Of String) FROM {"booked", "booked", "booked"})
seats.Add("C", new List(Of String) FROM {"C1", "C2", "booked"})
seats.Add("D", new List(Of String) FROM {"booked", "booked", "D3"})
Dim result = FindSeat(seats, "D")
Console.WriteLine(result) ' Output = D3
result = FindSeat(seats, "B")
Console.WriteLine(result) ' Output = "No free seat on that line"
End Sub
Function FindSeat(seats as Dictionary(Of String, List(Of String)), line as String) As String
if seats.ContainsKey(line) Then
dim seatLine = seats(line)
Dim placeFree = seatLine.FirstOrDefault(Function (x) x <> "booked")
if placeFree Is Nothing then
return "No free seat on that line"
else
return placeFree
End If
Else
return "Not a valid line letter"
End If
End Function
In Main, I have statically declared a Dictionary that contains as Key the line letter while a List(Of String) is used as value to declare the seats names and their current state.
Now to find a free seat I get the List(Of String) corresponding to the Line letter and the apply a simple FirstOrDefault to get the first seat not booked