VB.net 表達式不產生值錯誤

Question

我是 vb.net 的新手，一般編程很抱歉，如果這是一個基本錯誤，但我試圖在 vb.net 中制作 ax 和 o 的游戲，它一直說我的 CheckForWin 不會產生一個對我來說意義為零的值，當我查了一下，唯一的問題是關於將不同的代碼轉換為 vb.net 並且沒有提到我遇到的問題這是我的代碼：Public Class Form1

Dim Board(9) As String
Dim Player1 As String = "X"
Dim Player2 As String = "O"

Public Property X As String

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

End Sub

Private Sub ResetBoard()
    Do
        If CheckForWin() = True Then
            Board(0) = 0
            Board(1) = 0
            Board(2) = 0
            Board(3) = 0
            Board(4) = 0
            Board(5) = 0
            Board(6) = 0
            Board(7) = 0
            Board(8) = 0

        End If
    Loop Until Board(0) = 0
    Board(1) = 0
    Board(2) = 0
    Board(3) = 0
    Board(4) = 0
    Board(5) = 0
    Board(6) = 0
    Board(7) = 0
    Board(8) = 0
End Sub

Private Sub CheckForWin()
    If "0""3""6" = X Then
        ResetBoard()
    ElseIf "1""4""7" = X Then
        ResetBoard()
    ElseIf "2""5""8" = X Then
        ResetBoard()
    ElseIf "0""1""2" = X Then
        ResetBoard()
    ElseIf "3""4""5" = X Then
        ResetBoard()
    ElseIf "6""7""8" = X Then
        ResetBoard()
    ElseIf "0""4""8" = X Then
        ResetBoard()
    ElseIf "2""4""6" = X Then
        ResetBoard()
    ElseIf "0""3""6" = 0 Then
        ResetBoard()
    ElseIf "1""4""7" = 0 Then
        ResetBoard()
    ElseIf "2""5""8" = 0 Then
        ResetBoard()
    ElseIf "0""1""2" = 0 Then
        ResetBoard()
    ElseIf "3""4""5" = 0 Then
        ResetBoard()
    ElseIf "6""7""8" = 0 Then
        ResetBoard()
    ElseIf "0""4""8" = 0 Then
        ResetBoard()
    ElseIf "2""4""6" = 0 Then
        ResetBoard()
    End If
End Sub

End Class

問題出在這行代碼中： If CheckForWin() = True Then

Answer 1

這行代碼：

If CheckForWin() = True Then
    ...
End If

這將設置條件檢查以查看CheckForWin方法的結果是否為真。 問題是該方法是一個 Sub 例程，而不是 Function。

Function 表示一個返回值的代碼塊，而 Sub 也表示一個代碼塊，但它不返回值。

更重要的是，它看起來好像您陷入了無限循環。 ResetBoard調用CheckForWin ，后者調用ResetBoard ，后者調用...等等。

最簡單的做法是：

1. 將CheckForWin轉換為 Function
2. 停止在CheckForWin方法中調用ResetBoard
3. 當ResetBoard方法中的任何條件檢查為 True 時返回 True

這是一個例子：

Private Sub ResetBoard()
    ' check if there is a winner, if not then stop execution of the method early
    Dim isWin = CheckForWin()
    If (Not isWin) Then
        Return
    End If

    For index = 1 To 8
        Board(index) = 0
    Next
End Sub

Private Function CheckForWin() As Boolean
    Dim winningPatterns = {
        "0""3""6",
        "1""4""7",
        "2""5""8",
        ' etc...
    }
    Dim doAnyMatch = winningPatterns.Contains(X)
    Return doAnyMatch
End Function