Question

我正在创建一个用于课程作业的Visual Basic座位预订系统，它必须允许用户从A行到E行预订座位。对于B行，我设置它以便没有剩余座位，但是消息只是告诉用户没有足够的座位，并且最大可用座位数为0.我需要代码告诉用户没有剩余座位。我的代码如下：公共类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

如何设置我的代码，以便它告诉用户“此行中没有剩余席位”或其他内容？

Answer 1

不使用自定义类来设计问题域，一种简单的方法是使用词典

例如

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

在Main中，我已静态声明一个包含Key行号的词典，而List(Of String)用作声明席位名称及其当前状态的值。

现在要找到一个免费座位，我得到与线路信件相对应的List(Of String)，并应用一个简单的FirstOrDefault来获得第一个未预订的座位

在vb文档中为条件分隔消息

1 个答案: